问题补充:
--Who is the person talking with you just now?
-- Well, if you know, his name is David.
A. may
B. can
C. must
D. shall
答案:
A. may
B. can
(答案→)C. must
D. shall
解析:考查情态动词:A. may 可以,B. can能够, C. must 必须,偏要D. shall将会,句意是;--刚刚和你说话的是谁?--如果你偏要知道,是大卫。选C。