Liu Ming is said abroad for one year before he came to teach in our school．
A. to have studied
B. to study
C. to be studying
D. to have been studying
网友回答
(答案→)A. to have studied
B. to study
C. to be studying
D. to have been studying
解析：本题考查不定式的时态。根据语境Liu Ming已经在国外学习一年，且回来。故用不定式的完成时，选A。