According to Professor Johnson, we don't have to read the book if we don't want to, as it is              .

worthwhile

necessary

optional

serious

考查形容词词义辨析。句意：根据约翰逊教授的说法，如果我们不想读这本书，就不必读，因为它是可选择的。A. worthwhile值得的； B. necessary 必要的；C. optional 可选择的；D. serious 严肃的，认真的。根据“  we don't have to read the book if we don't want to”可知，这本书读不读都可以，由此可知它是“可选择的”。故选C项。

The most important promises we must keep are          we make to ourselves.

ones

those

these

them

考查代词。句意：我们必须遵守的最重要的承诺就是我们对自己做出的承诺。A. ones泛指上文提到的可数名词复数；B. those特指上文提到的可数名词复数；C. these这些；D.them他们。分析句子可知，为we must 是定语从句，修饰The most important promises，是句子的主语；be动词后缺少表演，we make to ourselves是定语从句，修饰空格处。根据句意，此处指上文提到的promises,由定语从句修饰表示特指，故用 those。故选B项。

If you want to catch the first bus you'd better         for the bus station immediately.

set up

set about

set down

set off

考查动词短语辨析。句意：如果你想赶上第一班公交车，你最好马上动身去车站。A. set up建立；B. set about开始做.....;C. set down 记下；D. set off 出发，动身。结合上文If you want to catch the first bus you'd better可知此处指“动身，出发”，应用set off。故选D项。

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。

We’ll make the final decision on our scheme. ______ you change your mind, please inform us as soon as possible.

Should

Were

Would

Had

考查虚拟语气的省略。句意：我们将对我们的计划做最后决定。如果你改变主意，请尽快通知我们。根据语境，此处用虚拟语气，表示与将来相反，从句用should+动词原形，省略if，should提前，陈述句是：If you should change your mind……。故选A。

The black teacher set a good example ____ all the rest of the group, _____ all peace-loving people.

to, who are

for, which was

to, which are

to, who were

[翻译]黑人教师给其他所有爱好和平的人树立了一个好榜样。[解析] D 解析：set an example to表示给某人树榜样，由此可以排除B;因先行词指人，故使用who引导非限定性定语从句，由此可以排除C; 根据时态的一致原则可知，此处应当使用一般过去时，故正确答案为D项。

Don’t mention that at the beginning of the story, or it may             the  shocking end.

give out

give away

give up

give off

考查动词短语辨析。句意：不要在故事的开头提到它，否则会泄露令人震惊的结局。A. give out分发；B. give away泄露；C.give up 放弃；D. give off发出（光），根据“the shocking end”可知，此处表示“泄露”。故选B项。

---Have you moved into        new office?

---No, the building is under          construction.

a; the

the; /

/; the

/; /

考查冠词。--你搬到新办公室了吗？--没有，大楼正在建设中。new office 谈话的双方都知道，所以是特指，需要用定冠词the,第二句under construction 指“正在建设中”，是固定搭配。故选B项。