—Who has taken my pen away?
— . He was here a moment ago.
A. It must be Li Ping
B. It is Li Ping take
C. Li Ping is
D. Li Ping must take
网友回答
(答案→)A. It must be Li Ping
B. It is Li Ping take
C. Li Ping is
D. Li Ping must take
解析： 本题是对情态动词的考查。句意表示肯定的推测用must，而it指问句中提到的who。