When Huawei P20 came out,         people couldn't wait to buy one in our town.

thousand

thousands

thousand of

thousands of

考查数词的用法。句意：当华为P20上市时，成千上万的人迫不及待的想在我们镇上买一台。thousnad意思是“千”，其前有具体数词修饰时，用其单数形式；当其前没有具体数词修饰时，用其复数形式，且与of 连用，thousands of“成千上万的”，这里没有具体数词修饰。故选D项。

Daniel has undertaken to keep the secret, so he won’t tell anyone even though ______.

asked to keep

to be asked

to ask

asked to

考查省略和过去分词。句意：丹尼尔答应保守这个秘密，所以即使问他也不会告诉任何人。此处是even though引导的让步状语从句，从句主语和主句主语都是he，和ask之间是被动关系，相同的主语和be动词可以省略，所以这里是过去分词作状语，且ask sb. to do sth.可以省略与前面相同的部分，只留下动词不定式符号to。故选D。

It has been warned that        to the surroundings with people infected by Covid-19 without any

protection can lead to severe result.

being exposed

exposed

having exposed

to expose

考查非谓语动词。句意：有人警告称，在没有任何保护措施的情况下，暴露在有感染 Covid-19的人环境中会导致严重的结果。分析句子结构可知expose在句中应用非谓语动词形式，表示“暴露”短语为be exposed to,且从句中缺少主语，expose 与主语people是被动关系，故应用动名词的被动式作主语。故选A项。

People           about what our future will look like for thousands of years.

have been wondering

wonder

wondered

will wonder

考查动词时态。句意：数千年以来人们一直想知道我们未来是什么样子。根据时间状语 for thousands of years可知，描述从过去开始一直持续到现在的动作，用现在完成进行时。故选A项。

Which of the following does not contain the sound [ae]?

grade

glad

bad

land

考查语音。句意：下面哪个不包含这个发音[ae]? grade的发音是[greId]; glad的发音是[glaed]; bad的发音是[baed]; land的发音是[laend]。故选A项。

          no bus,we had to walk home.

There was

There being

Because there being

It being

考查独立主格结构。句意：没有车，我不得不走路回家。根据句意，表示“存在”，要用there be 句型；分析句子可知，设空处应用非谓语动词，there be只有主动形式，故用现在分词；因为非谓语动词有自己独立的的主语no bus,所以此处是独立主格结构。故选B项。

---I'm sorry,but it's my seat.

---           I didn't know it's yours.

What if

I beg your pardon

That's all right

What for

考查交际用语。句意：---对不起，这是我的座位。---请原谅。我不知道这是你的。A. What if如果.....将会怎么样；B. I beg your pardon. 对不起，请原谅；C.That's all right没关系；D. What for为什么。根据"Idon't know it's yours."可知坐了别人的座位，请求别人原谅。故选B项。

It is six months         the online class started.

that

until

before

since

考查固定句型。句意：在线课程已经开始六个月了。A. that 那，那个；B. until直到..... 为止；C. before在.....之前；D. since自.....以来。分析句子可知，句中涉及固定句型“ It is +一段时间+since引导的时间状语从句”，意为“自从......以来已经有多长时间了”，since从句中用非延续性动词。故选D项。

The old rules have to be          because they only applied to the circumstances that existed when they were made a hundred years ago.

developed

established

observed

revised

考查动词的辨析。句意：老的规则需要被修改因为它们只适合一百年制定时的状况。A.develop发展；培养；B.establish建立；C.observe观察；D.revise修改，由because they only applied to 可知它只适用于以前，需要修改。故选D项。