21.There are _______ different species of cats.
A. a few hundreds B. a few hundreds of C. a few hundred of D. a few hundred
22. I tried to ______ in my speech we were all grateful for his help.
A. speak B. tell C. express D. convey
23. There is no _______ to be gained from endlessly discussing whose fault it was.
A. use B. consequence C. profit D. effect
24. The cancer risks _____ with smoking have been well proved.
A. combined B. associated C. caused D. joined
25. The new law was generally admitted _______ difficult to carry out.
A. being B. was C. to be D. it's
