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。

When            to someone,I usually say, "Pleased to meet you."

introduce

introduced

introducing

am introduced

考查过去分词和省略。句意：当我被介绍给别人时，我通常会说：“很高兴认识你”。根据句子结构可知，本句是when引导的时间状语从句，原句when I am introduced to someone,这里当从句主语与主句主语一致时，并且从句的谓语动词有be这时从句的主语与be同时省略，所以空格处introduced。故选B项。

It was along the Mississippi River _________ Mark Twain spent much of his childhood.

how

which

that

where

此处构成It was...that...强调句式，句中强调了介词短语along the Mississippi River。故选C。

Inside the window hangs a         carved out of this piece of wood by the artist.

decoration

destination

departure

discipline

考查名词辨析。句意：窗户边上挂着一幅被艺术家由这块木头雕刻的装饰品。A. decoration装饰，装饰品；B. destination目标； C. departure 离开；D. discipline纪律。窗边应挂着装饰品。故选A项。

When           another country, you should be aware of those differences and respect them.

visit

to visit

visiting

visited

考查非谓语动词。句意：当拜访另一个国家时，你应该知道这些不同之处并尊重它们。分析句子可知，空格处应填非谓语动词和when一起构成时间状语，逻辑主语you和visit之间是主动关系，应用现在分词。故选C项。

Your       as a student will be excellent if you develop a habit of reflecting on how you learn.

operation

growth

performance

character

考查名词辨析。句意：作为一名学生，如果你养成课后复习的好习惯，那么你的表现就会很优异。A.operation 操作； B. growth生长；C. performance 表现；D.character性格。学生如果有课后复习的好习惯，会表现优秀。故选C项。