答案：人民群众。
A. enough
B. plenty
C. as much as
D. a great deal of
解析：解析:enough 修饰名词,在名词之前解析:plenty+ofAs much as 不能修饰名词A great deal of 修饰不可数名词。
A. what
B. how
C. when
D. where
A. forty
B. forty’s
C. forty’s years old
D. forties
A. 
B. 
C. 
D. 
解析：试题解析:本题考查的知识点为-阶微分方程的求解.可以将方程认作可分离变量方程;也可以将方程认作-阶线性微分方程;还可以仿二阶线性常系数齐次微分方程,并作为特例求解.
解析：解析:
A. with vain
B. on vain
C. in vain
D. of vain
A. will rain
B. rains
C. rain
D. has rained
解析：解析:(take place 举行;
A. will we
B. shall we
C. do we
D. are we
A. 
B. 
C. 
D. 
解析：解析:
