单项选择题
A. do simply as others expect B. conceal one’s shameful past C. always defy others’ opinions D. retreat from various pressures
A. help cure insect-born tropical diseases B. promote environmental protection C. stop the chemical companies’ business D. protect African children against insects
A. attend courses of one’s own choice B. get a scholarship in a desired specialty C. produce students with new horizons D. ask teachers to stay long in their jobs