Hardly____the house when he was caught.
A the thief had entered B.entered the thief C.had the thief entered D.was the thief entering

答案：C 我选D， 这里难道不是`逮个正着`的意思吗

Not until yesterday afternoon___raining.
A.it had stopped B. had it stopped C.it stopped

答案：C， 為甚麽不选B not until 放句首不是倒装吗，这里怎么不用

Out (ran the dog) after the door was opened.
这里的 ran the dog可以改成 did the dog run 吗？

Can you tell me the name of the factory___you visited last week?
A.what B.where C.不填 D.when

答案：C， 我选A，visited 后面不是缺Object 吗，怎麽不要填了呢

The factory___his mother works is in the east of the city
A.that B.which C.on which D.where
答案：D 这题和上一题有什么区别？

1 That is the reason___he wasn't here yesterday.
2 That's the reason___he can't say.
答案：1 why 2 that
这二者有什么区别没有，答案能互换吗？

Whoever visits the Great Wall will be struck by it.
Whoever能改成anyone who吗？还是改成 anyone？

1.hardly....when../刚....就..../ 一般的来说用这个句型时,为体现一个时间的先后,hardly接过去完成时,when接一般过去时.
他刚一进房间（显然动作已经完成）就被逮到了。
而且进房间这个动作也不能是进行时，不能一直在进啊

Not until 在句首应该倒装. 我也想知道为什么选这个选项,是不是答案错误啊.

Can you tell me the name of the factory___you visited last week?
visit是及物动词,应该接关系代词that,that在从句中做宾语可省略.
这个句子应该用定语从句.what只能引导名词性从句.

The factory___his mother works is in the east of the city
A.that B.which C.on which D.where
答案：D 这题和上一题有什么区别？
这道题区别是work是不及物动词,只能用关系副词.D.where是关系副词.

这里的 ran the dog不能改成 did the dog run 。

the reason why/that 没什么大的区别,我认为可以互换.

你说的是:先行词和关系词二合一
例:Whoever spits in public will be punished here.
　　 (Whoever 可以用 anyone who 代替) 但是不能改成anyone,那样就有两个谓语动词了。