1. We should learn from those ______ are always ready to help others.
A. who  B. whom  C. they    D. that
2. Mr. Herpin is one of the foreign experts who ____ in China.
A.works  B. is working C. are working D. has been working
3 Tom is the only one of the students who ______ to Shanghai. .
A.have gone  B. have been   C. has been  D. had gon