Though it is a          job, he  still devotes much time and energy to it.

poor-paying

poorly-paying

poorly-paid

poor-paid

考查构词法。本题中考查了复合形容词的构词法，“使用副词+过去分词” 构成新的形容词，如“newly-discovered”最新发现的；本句中“poorly-paid报酬极少的”。句意：尽管这是一份报酬极少的工作，但他仍然花了很多时间和精力做它。故选C项。

If you don't understand something, you may resrarch, study, and talk to other people          you figure it out.

because

though

until

since

考查连词。句意：如果遇到不懂的东西，你可以搜索、研究，和别人交流直到弄明白。A. 因为； B. 尽管；C.until直到；D.since自从，因为。根据句意可知，until符合语境。故选C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。

Suddenly a good idea occurred to her, but she couldn't find any paper           .

 to write

to write on

written

writing on

考查了非谓语动词。句意：她突然有了一个好主意，但是她找不到纸来写下它。根据句意可知，这里用不定式表目的，而且固定搭配是write sth on the paper。故选B项。

           is reported in the newspaper, the epidemic situation is getting better now in China.

It

As

That

What

考查定语从句。句意：正如报纸上报道的那样，中国的疫情正在好转。分析句子结构可知，空格处引导一个非限制定语从句，先行词是整个主句内容，关系词在从句中做主语，表示“正如”，应用as引导，as 引导非限制性定语从句 ，位置比较灵活，可放在主句前。故选B项。

A study shows the students who are engaged in after-school  activities are happier than        who are not.

ones

those

these

them

考查代词。句意：一项研究表明，参加课外活动的学生比不参加课外活动的学生更开心。空格处代词与the students是对应关系，可以用the ones 或者those替代。“them”指代前面提到的复数名词，不能与the students形成对应关系，“these”一般不用定语从句修饰。故选B项。