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。

What some people regard as a         is seen as a plus by many others.

duty

drawback

failure

faith

考查名词词义辨析。句意：一些人认为是一个缺点，而其他许多人则认为这是一个优点。A.duty责任；B.drawback缺点； C. failure 失败；D. faith信念。根据空后plus“优点”可知，空处需用drawback“缺点”与之对应。故选B项。

Like other animals, we are          until we know it is safe to relax.

on purpose

on fire

on guard

on duty

考查介词短语辨析。句意：像其他动物一样，我们在知道安全的时候才放松警惕。A.on purpose 故意；B. on fire着火；C.on guard 警惕；D.on duty值班。结合后文we know it is safe to relax，可知我们在知道安全的时候才放松警惕。故选C项。

The student completed this experiment to make come true         Professor Joseph had said.

that

what

when

where

考查名词性从句。句意：为了使约瑟夫教授所说的成为现实，这个学生完成了这个实验。        Professor Joseph had said作make的宾语从句，该从句中，空格处在从句中作said的宾语，表示“......所说的话”，因此应用what 引导该从句。故选B项。

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。

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。