2.The biggest whale is　　blue whale，which grows to be about 29 meters long－the height of　　9­story building.

解析：句意：最大的鲸鱼是蓝鲸，可以长到大约29米长--其高度相当于一座9层楼的高度。前一空格处是“the+单数可数名词”表类指；后一个空格处是泛指。

答案：the；a

1.Let's go to 　　 cinema－that'll take your mind off the problem

for 　　 while.

解析：go to the cinema与for a while均为习惯搭配，分别指“去看电影”，

“一会儿”。

答案：the；a

10.What the children in the mountain village need　　(be) good books.

解析：what引导的主语从句作主语时，谓语动词要根据后面的名词的数来决定，此处要用复数形式。

答案：are

9.　　(Have) either of your parents come to see you recently？

解析：either of ...构成的短语作主语时，谓语动词通常用单数。

答案：Has

8.Both rice and wheat　　(be) grown in our country.

解析：both...and...连接两个并列主语时，句子的谓语动词要用复数形式。

答案：are

7.Mathematics　　(be) the language of science.

解析：此处mathematics为学科名词，作主语时谓语动词要用复数形式。

答案：is

6.Stories of the Long March　　(be) popular with the young people now.

解析：主语Stories of the Long March是书名，谓语动词要用第三人称单数形式。

答案：is

5.Three million tons of coal　　(be) exploited every year in the city.

解析：主语为coal，是不可数名词。根据题意，此处要用被动语态。

答案：is

4.There　　(be) a lot of rubbish on the floor so I asked Mary to sweep it up.

解析：there be句型中be动词的单复数取决于其后的主语，a lot of rubbish(不可数名词)，因此后面谓语动词要用单数。答案：was

3.The Olympic Games in the year 2008 　　(be) held in Beijing of China， which 　　(be) known to us all.

解析：主语the Olympic Games 意为：奥运会，谓语动词多用复数形式；后半部分为which引导的非限制性定语从句，其谓语动词要用单数形式。

答案：were；is