851.There _____ be any difficulty in passing the PETS oral test since you have practiced a lot in school.
A.mustn't
B.shan't
C.shouldn't
D.needn't
852.He ____ have come here yesterday,_____ he?
A.mustn't;did
B.couldn't;has
C.must;haven't
D.must;didn't
851.答案是C;根据题意，此处表示按常理推断不应该。
852.答案是D;考查含有情态动词的反意疑问句。根据yesterday可知用一般过去时。
