21.While the chairman was giving a talk at the meeting,some

21.While the chairman was giving a talk at the meeting,some workers at the back paid no attention and kept ____.
A.chattering
B.enduring
C.relieving
D.mentioning
满分：2 分
22.David’s mother insisted that he ____before ten every night.
A.must go to bed
B.goes to bed
C.go to bed
D.has gone to bed
满分：2 分
23.The cardigan is particularly to my taste,____ its price.
A.except
B.besides
C.except for
D.in addition to
满分：2 分
24.Forced by his heartless son into signing the paper,the poor old man could do nothing but tremble and ____.
A.flutter
B.splutter
C.chatter
D.clatter
满分：2 分
25.The farmers ____ a mysterious object flying over when they made their way home.
A.kept up with
B.caught sight of
C.made use of
D.held themselves in
满分：2 分
26.The popular young doctor is the ____ director of the medical research institute.
A.Current
B.radical
C.average
D.typical
满分：2 分
27.His children found it hard to ____ him from the simple way of life in the countryside.
A.skip
B.dissuade
C.tighten
D.endure
满分：2 分
28.Don’t expect a millionaire to be dressed expensively all the time; a rich man does not ____ show off his wealth.
A.reluctantly
B.occasionally
C.emotionally
D.ecessarily
满分：2 分
并请帮我分析一下选的理由，

21.A 这题完全理解意思吧,只有A的意思是喋喋不休,完整句子意思是 当主席在会议上演讲的时候,一些坐在后面的工人一点不注意而且还在那喋喋不休.
22.C insist on sth 或者 insist that+ 句子（sb.do sth.）
例句I insist on your taking/insist that you take immediate action to put this right.
23.B 一般在 besides 前面都有逗号分开,而其他三个词并不需要用符号.
24.C tremble and chatter 这个我觉得应该是个词组,意思是颤抖和牙齿打颤,表示害怕!
25.B caught sight of 看到(忽然看见,发现,看到一眼),在回家路上突然看到一个神秘物体在上空飞过.
26.A Current当前的（your current employer）是医学研究机构的现任领导
27.B dissuade dissuade sb.from 劝阻某人不做某事,只有这个单词能接from!他的孩子们发现很难让父亲改变简朴的乡村生活.
28.D 理解意思,不要以为百万富翁整天都是穿着昂贵!富人不是（ ）炫耀他的财富!根据前文,我觉得应该是,不是经常炫耀财富,但选项ABC分别是不勉强的,偶然的,在感情上,肯定讲不过去的.只有选D了,但D似乎拼写错了,意思应该是经常吧,富人也不经常炫耀.