问题补充:
201. Tom into the house when no one.
A. slipped; was noticing
B. had slipped; noticed
C. slipped; had noticed
D. was slipping; noticed
答案:
(答案→)A. slipped; was noticing
B. had slipped; noticed
C. slipped; had noticed
D. was slipping; noticed
解析:可联系答.案.网客服索取。