Six lectures on ``Open problems on discrete subgroups of Lie groups", Tsinghua University, China, December 15-24, 2011.

Three talks at Zhejiang University, July and August, 2006.

Eight one-hour lectures on "Arithmetic groups and reduction theory" at the summer school on "Automorphic forms and representation theory", Center of Mathematical Sciences, Hangzhou, July 2004.

Eight one-hour lectures at the summer school in Hangzhou, August 2003.

A series of 8 hours lectures at an instructional workshop on Lie groups and related topics at Zhejiang University, China, June 17-29, 2002

One of the three main lecture series (6 hours) at the European Summer School in Group Theory held in Marseille-Luminy, France, July 2--July 13, 2001.

Three weeks lectures on compactifications of symmetric spaces in May, 98, Hong Kong University

Seven weeks lectures on symmetric spaces in June-July, 99, Hong Kong University

Four weeks lectures on Harmonic analysis on symmetric spaces in June, 2000, Hong Kong University.

Colloquium, Columbia University, October 2012.

Colloquium, Mathematics Institute, Academy of Science, August 2012.

Conference on complex geometry, singularities, Tsinghua University, 2012.

Seminar, Beijing University, July 2012.

Conference on differential geometry, Capital Normal University, July 2012.

A public lecture for high school teachers in Zhu-Hai City, China, July 2012.

Conference: Geometry and Topology in Samos, Greece, June 11-15, 2012.

Conference at University in Strasbourg, June 2012.

A colloquium talk, Rutgers University, April 27, 2012.

A seminar talk, The Mittag-Leffler Institute of Mathematics, February 28, 2012.

Conference on Geometric Analysis, University of California, Irvine, January 14--17, 2012.

Conference: Geometry and Arithmetic around Teichm\"uller Theory, Istanbul, Turkey, November 15--19, 2011.

A colloquium talk, Binghamton University, November 10, 2011.

A seminar talk, Binghamton University, November 10, 2011.

A talk at the Algebraic Geometry/Number Theory Seminar, Johns Hopkins University, October 18, 2011.

A talk at the Complex Geometry Seminar, Johns Hopkins University, October 18, 2011.

The hyperbolic and Riemannian geometry of surfaces and other manifolds, October 31-November 4, 2011, the Centro Stefani Franscini in Ascona, Switzerland.

The second National conference on Math and Culture Courses, Nankai University, China, July 14-15, 2011.

Colloquium, University of T\"ubingen, Germany, June 24, 2011.

A lecture series at summer school: Geodesic Flow, Negative Curvature and Isomorphism Conjectures, University of G\"ottingen, Germany, June 21-24, 2011.

Seminar, University of Karlsruhe, Germany, June 16, 2011.

Seminar, University of Strasbourg, France, May 30, 2011.

2011 Bloomington Geometry Workshop, Indiana University, Bloomington, March 11-13, 2011.

A public lecture for high school students at the Fifty-Fourth Michigan Mathematics Prize Competition, Sagnaw Valley State University, Michigan, February 26, 2011.

Th\'eorie des modules en math\'ematiques et en physique, Universite de Strasbourg I, September 2-4, 2010.

Buildings, Finite Geometries and Groups, An ICM satellite conference, Bangalore, August 29-31, 2010.

Spectral analysis on noncompact manifolds, Hausdorff center for mathematics, Bonn, June 24-26, 2010.

Workshop on Arithmetic Groups and their Applications in Combinatorics, Geometry and Topology, University of Virginia, April 15-18, 2010.

Seminar, Univ of Michigan, Flint Campus, April 2, 2010.

Global Analysis and Automorphic Forms, Hebrew University, Einstein Institute of Mathematics, Jerusalem, March 14-19, 2010.

The 17th SCGAS, University of California at Irvine, Feb 20-21, 2010.

Colloquium, University of Toronto, January 13, 2010.

Lattices, Coxeter Groups, and Buildings, an AMS special session, Boca Raton, FL, October 30 - November 1, 2009.

Cao Xihua Mathematics Forum, East Normal University, Shanghai, July 28, 2009.

International Workshop on Quantized Algebras and Physics, Chern Institute of Mathematics, Nankai Univ, China, July 23--26, 2009.

The 3rd International Workshop on Matrix Analysis and Applications, Hangzhou, July 9-13, 2009.

Colloquium, University of M\"{u}nster, May 28, 2009.

String theory, general relativity and partial differential equations, Harvard University, May 25, 2009.

Colloquium, UCSD, May 14, 2009.

Geometry seminar, Stanford University, May 13, 2009.

A colloquium talk at Penn State Univ, Apr 9, 2009.

A talk at Number Theory seminar, Penn State Univ, Apr 9, 2009.

A talk at an Oberwolfach workshop, Germany, November 16--22, 2008.

A colloquium talk at Datrmouth College, November 13, 2008.

A talk at Geometry seminar at Datrmouth College, November 13, 2008.

A talk at a workshop at American Institute of Mathematics, September 8--12, 2008.

A talk at Geometry and Topology seminar at Fudan University, Shanghai, July 23, 2008, China.

One talk at an international summer school: Geometry of Teichm\"{u}ller spaces and moduli spaces of curves, July 14-July 20, 2008, Hangzhou, China.

Two talks at an international summer school: Transformation Groups and Orbifolds, June 30-July 14, 2008, Hangzhou, China.

A talk at a workshop: Locally symmetric spaces, Banff, May 18--23, 2008.

A seminar talk at Michigan State University, Apr 1, 2008.

A talk at the 42nd Spring topology and dynamics, March 13-15, 2008, Wisconsin.

A colloquium talk at University of Karlsruhe, February 13, 2008.

A plenary talk at {\em the Fourth International Congress of Chinese Mathematicians}, Hangzhou, China, December, 2007.

A plenary talk at {\em the Sixth Workshop on Lie Theory and Geometry}, November 13-17, 2007, Argentina.

A talk at the workshop {\em Group Embeddings: Geometry and Representations} at Banff, Sep 16--Sep 21, 2007.

A talk at the workshop {\em Topological and Geometric Rigidity} at Banff, Jul 29--Aug 03, 2007.

A talk at {\em the Fourth International Conference on Representation theory}, July 16--20, Tibet, 2007.

A talk at a summer school {\em Cohomology of groups and algebraic K-theory}, July 1--13, 2007, Hangzhou, China.

A seminar talk at Univ of California, Irvine, June 6, 2007.

A talk at a conference {\em Buildings and Groups}, May 20--26, 2007, Ghent, Belgium.

A colloquium talk at Lehigh University, October, 2006.

A colloquium talk at Vanderbilt University, September, 2006.

A seminar talk at Henan University, August, 2006.

A public lecture at Henan University, August, 2006.

A talk at Univ of Toronto, May 2006.

A talk at University of Chicago, April 2006.

A talk at University of Toledo, April 2006.

A talk at Northesatern University, February 25, 2006.

A talk at a workshop "Analysis and geometric singularities" at Oberwolfach, August 21-27, 2005.

A talk at a symposium "Lie groups: from topology to arithmetic", in memory of Armand Borel, June 29-July 6, 2005, Zurich and Geneva, Switzerland.

A talk at a conference "Scattering theory and singular spaces", May 27-30, 2005, Northwestern University, 2005.

An invited talk at "The International Congress of Chinese Mathematicians", Hong Kong, December 17-22, 2004.

A talk at AMS special session "Index Theory and the Topology of Manifolds", AMS Sectional Meeting in Nashville, October 16-17, 2004.

A talk at the international conference on "Algebraic groups, arithmetic groups, automorphic forms and representation theory" in memory of Armand Borel, Zhejiang University, July 2004.

A talk at workshop "Spectral theory and automorphic forms", CRM, Montreal, May 3--8, 2004.

A talk at workshop "Locally symmetric spaces", Oberwolfach, September 28 -- October 4, 2003.

A colloquium talk at University of Minnesota, November, 2002.

A talk at joint geometry and Lie group seminar at University of Minnesota, November, 2002.

A talk at analysis seminar at MIT, November, 2002.

A talk at the ICM satellite conference "Harmonic analysis and its applications", Hangzhou, August, 2002.

A talk at Park City/IAS Math Inst "Automorphic forms and applications", the research program, July 2002.

A talk at "the Midwest workshop on representation theory, automorphic forms, and related subjects", Notre Dame University, April, 2002.

A colloquium talk at University of Arizona, March 2002.

A seminar talk at University of Arizona, March 2002.

Workshop "Arithmetic groups and their cohomology groups", ESI, Vienna, Jan 2002.

A special session of AMS meeting at Ohio State Univ, September, 2001.

An international conference in honor of Prof. Su's 100 birthday at Zhejiang Univ, July, 2001.

Workshop " (Locally) Symmetric Spaces", Univ of Nancy-I, France, June, 2001.

A seminar talk at University of Vienna, May 2001.

Colloquium Talk at Wayne State University, December, 2000.

JAMI seminar, Johns Hopkins University, November, 2000.

Lie group seminar at Cornell University, October, 2000.

Colloquium Talk at University of Georgia, October, 2000.

Geometry and analysis seminar at Ohio State University, March 2000.

Colloquium Talk at University of Kentucky, January, 2000.

Zhejiang University, China, December, 1999.

Banach Center of Math, Warsaw, September, 1999.

Geometry and analysis seminar at Chinese University of Hong Kong, June 1999.

Analysis and geometry seminar, UC Berkeley, April 1999.

International Congress of Chinese Mathematicians, Beijing, December, 1998.

Geometry seminar at Univ of California, Irvine, November, 1998.

IAS/Park City Math Inst ``Representation Theory of Lie Groups'', July, 1998.

A conference at Oberwolfach in Germany on "Geometric Analysis and Singular spaces", June, 98.

Geometry and Topology seminar at University of Chicago, June, 98.

Colloquium talk at University of Hong Kong, Department of Mathematics, May, 1998.

A special session of AMS meeting in Kansas, March, 1998.

A special session of AMS meeting in Kentucky, March, 1998.

Lie group seminar at Yale University, November, 1997.

Lie groups and representation theory seminar at University of Maryland, November, 1997.

Workshop on Microlocal methods in geometric analysis at the Fields Institute, October 1997.

A special meeting of AMS meeting at University of Montreal, September, 1997.

European Research Conference on ``Mathematical Analysis'' in Spain, June 1997.

The New York Journal of Mathematics Conference, Albany, June 1997

A special session of AMS meeting at Wayne State Univ., May 1997.

Lie Group Seminar at the Graduate Center of CUNY, New York, February 1997.

A special session at the annual AMS meeting in San Diego, January 1997.

Colloquium talk at University of Waterloo, September 1996.

The Ontario analytic geometry seminar, September 1996.

Several Complex Variables Seminar at MSRI, March 1996.

Geometry and Topology Seminar at McGill University, March 1996.

Colloquium talk at University of Tennessee, Department of Math, October 1995.

Complex Analysis Seminar at Univ of Maryland, May 1995.

The Third Math Society of Japan Research Institute, Hayama, Kanagawa, Japan, March 1995.

Lie Group Seminar at the Graduate Center of CUNY, New York, February, 1995.

Member Seminars, Institute For Advanced Study, February 1995.

A special session of AMS annual meeting at San Fransico, January 1995.

Differential Geometry Seminar at Courant Institute of Math. Sci., November 1994.

Workshop on Spectral Theory of Automorphic Forms at MSRI, Berkeley, October 1994.

Differential Geometry Seminar at University of Maryland, October 1994.

Colloque Pierre Eymard \& Colloque tournant d'Analyse Harmonique, Nancy, France, June 1994.

Geometric Analysis, a special session of AMS meeting at Brooklyn, New York, April 1994.

Differential Geometry Seminar at the Graduate Center of CUNY, New York, April 1994.

Geometry and Analysis Seminar at Johns Hopkins University, November 1993.

Partial Differential Equation Seminar at MIT, November 1993.

The Summer Workshop on Degenerating Elliptic Operators at Stanford University, August 1993.

Spectral Geometry at the AMS-IMS-SIAM Summer Research Conferences in the mathematical Sciences, University of Seattle, July 1993.

15th Nevanlinna Colloquium at University of Michigan, June 1993.

Differential Geometry Seminar at Harvard University, October 1992.

Algebraic Geometry Seminar at MIT, December 1991.

Analysis Seminar at University of Maryland, February 1991.

I have also given numerous talks at seminars at University of Michigan.

Conference on Automorphic Forms, Geometry and Analysis, IAS, Princeton, October 1996.

Workshop on Algebraic and Differential Geometric Methods in Complex Analysis, MSRI, March 1996.

Harmonic Functions on Graphs and Buildings at the Graduate Center of CUNY, New York, November 1995.

Scattering Theory at Johns Hopkins University, Baltmore, April 1995.

AMS Summer Institute on Stochastic Analysis at Cornell University, July 1993.

AMS Summer Institute on Differential Geometry at UCLA, August 1990.