35. A wide vocabulary is the key to successful language learning but don’t try to learn too much ______.

A. at least　　　　　　 B. at once　　　　　　 C. at last　　　　　　　 D. at most

34. The importance of saving gas ______ be stressed too much. Automobiles use up some 70 billion gallons of gas a year.

A. cannot　　　　　　 B. mustn’t　　　　　 C. shouldn’t　　　　 D. may not

28. Whether you believe it or not, it is ______ that causes your illness.

A. because of your overweight

B. because you are overweight

C. you are so overweight

D. your being overweight

32. Because of _____ mail we receive, we may not be able to reply to your letter. Please remember to include your full name with your letter.

A. a great many of　　　　　　　　　　 B. a large number of

C. the large amount of　　　　　　　　　　 D. a great plenty of