A. may B. couldn't C. should D. needn't

解析：根据句意"不可能是词汇导致了你习题中的问题，因为你知道了很多词汇。"可以得出此处表示否定的推测。

答案：B。

2. (2014全国大纲)Although you ______find bargains in London, it's not generally a cheap place to shop.

A. should B. need C. must D. can

解析：根据句意"尽管你能在伦敦找到便宜货，但是一般不是购物便宜的地方。"此处can意为"能"的意思。

答案：D。

3. (2014陕西)My book, The House of Hades, is missing. Who ________ have taken it?

A. need B. must C. should D. could

解析：根据句意"我的书丢了。可能会是谁拿走了呢？"从语境分析,could在此处表示对过去"可能性"的推测。

答案：D。

4.(2013浙江) I______ myself more-it was a perfect day.

A. shouldn't have enjoyed B. needn't have enjoyed

C. wouldn't have enjoyed D. couldn't have enjoyed

解析：根据句意"我从未玩得更开心过--这是完美的一天。"shouldn't have done表示"本不应该做而事实上已经做了"；needn't have done表示"本没有必要做而事实上已经做了"；wouldn't have done用于虚拟语气；couldn't have done表示"不可能做过"。此处用not和比较级连用表达最高级的含义,意为"从未比这更高兴过"。

答案：D。

5. If I______ it with my own eyes, I wouldn't have believed it.

A. didn't see B. weren't seeing C. wouldn't see D. hadn't seen

解析：根据句意"如果不是亲眼所见，我根本不会相信"，本题考查虚拟语气。与过去事实相反。"

答案：D。

基础演练

1. --- What does the sign over there read?

---"No person _______ smoke or carry a lighted cigarette, cigar or pipe in this area."

A. will B. may C. shall D. must

2. ---I'm sorry. I______ at you the other day.

--- Forget it. I was a bit out of control myself.

A. shouldn't shout B. shouldn't have shouted C. mustn't shout D. mustn't have shouted

3. My MP4 player isn't in my bag. Where _______ I have put it?

A. can B. must C. should D. would