【点评】考查介词短语，注意in one's forties的用法。

37．There are children in my grandfather's family and he is the child of the family. A. nine; fifth B. nine; five C. ninth; five D. ninth; fifth

【答案】 A

【解析】【分析】句意：我外公家有9个孩子，并且他是第五个孩子。A.nine；fifth9；5；

B.nine；five 9；5；

C.ninth；five 第九；5

D.ninth；fifth 第九；第五。根据第一个空可知，此处填入基数词，答案为nine，第二个空填入序数词，答案为fifth，故选A。

【点评】考查了基数词与序数词的辨析，注意，区分两者。

38．In our class of the students girls.

A. third fifths; is

B. third fifth; are

C. three fifth; is

D. three fifths; are

【答案】 D

【解析】【分析】句意：我们班五分之三的学生是女生。分数表达方式：分子要用基数词，分母要用序数词，当分子超过一时，分母后要加s。五分之三的正确表达是three fifths；带有分数的短语作主语时，谓语动词由分数后面的名词形式来决定，students是复数形式，谓语动词要用are，故选D。

【点评】考查分数的基本构成。注意其作主语时谓语动词形式的选择。

39．—____________of volunteers will be needed for the 2020 Olympic Games.

—Let's go and____________ them.

A.Thousands, join

B.Thousand, be a member of

C.Three thousand, take part in

D.Thousands, be in

【答案】A

【解析】【分析】句意：——2020年奥运会将需要几千名志愿者。——让我们去加入他们吧。thousands of，几千，join sb，加入，和某人一起，故选A。

【点评】考查数词，注意join sb的用法。

40． of the land in that district covered with trees and grass.

A. Two fifths; is

B. Two fifth; are

C. Two fifth; is

D. Two fifths; are

【答案】 A

【解析】【分析】句意：在那片区域五分之二的土地被树和草覆盖着。分数由基数词和序数词构成，分子用基数词，分母用序数词，分子大于1时，分母用复数，所以五分之二的