16. It has been found that how close parents are to their children ______ a rather strong influence on the development of the children's character. ( )��

　　A. have B. has

　　C. having D. had��

　　17. The audience ______ requested to remain seated during the intermission. ( )��

　　A. are B. is

　　C. were D. be��

　　18. During extremely hot weather, elephants require both mud and water to keep their skin cool ______ they have no sweat glands. ( )��

　　A. and B. so��

　　C. because of D. due to the fact that��

　　19. His score of the final English exam is higher than ______ in his class. ( )��

　　A. anyone's else B. anyone else��

　　C. anyone's else's D. anyone else's��

　　20. He has been staying at home ______ days. ( )��

　　A. these all last few B. these last few all��

　　C. all these last few D. these last all few��