21.It has long been known that there is an electric field ______.

a. inside the earth b. inside earth c. inside an earth d. on earth

22.______ much harder work, the volunteers were able to place the raging forest fire______.

a. By the means of…under the control b. By means of…under control

c.By means of…under a control d. By a means of…under control

23.No sooner had the man departed than the tree began dropping coffee beans ______.

a. by the thousand b. by a thousand c. by thousands d. by thousand

24.He expressed ______ of their having ever been married.

a. the doubt b. a doubt c. doubt d. an doubt

25.He saw through the little boy’s tricks ______.

a. at glance b. at the glance c. at some glance d. at a glance

26.Their victory is ______,for they’ve lost too many men.

a. out of question b. out of the question c. out question d. of question

27.Many a girl wants to become ______.

a. some secretary b. a secretary c. secretary d. secretaries

28.He grabbed me ______ and pulled me onto the bus.

a. a arm b. an arm c. the arm d. by the arm

29.I’ll come in ______ minute; in fact I’ll come ______ moment I’m through.

a./…the b. a…the c. the…a d. /…/

30.This is one of ______ interesting books on your subject.

a. the most b. the most of the c. most d. most of the