问题

John was fired by his factory and only then ________ how wrong he was to be lazy and careless.[ ]

A: had he realized
B: he had realized
C: did he realize
D: he realized

正确答案是：

同类题型

The history teacher often tells his students to________the knowledge they’ve learned accordingto chapters.[ ]

Kites ________ messages in the war in the past.

It doesn’t often snow in my hometown in winter, but it ___be rather cold sometimes. [ ]

One solution to this problem now is sustainable development.

The thirteen stars on the flag _ the thirteen colonies that announced independence first.[ ]