问题

By the time he realizes he ________into a trap, it’ll be toolate for him to do anything about it.[ ]

A: walks
B:walked
C: has walked
D: had walked

正确答案是：

同类题型

Is this __________ ruler—No, it’s my ruler. __________ is over there.

This is a picture of DrYuan, a scientist ____ is well known in our country

Is there _____ today’s newspaper

I _____ to bed when the telephone rang

, the classroom is so dirty Itneeds ______ before we begin our class