I don’t think Mary and Sue before, ?
A. have met; haven’t they
B. have met; have they
C. have seen; do I
D. have seen; don’t they
网友回答
A. have met; haven’t they
(答案→)B. have met; have they
C. have seen; do I
D. have seen; don’t they
解析：主句是第一人称，而且谓语动词是think, find, believe,make等，反意疑问句要和宾语从句一致；而且还得注意否定的转移问题。