15.- Thank you for calling.
-

45.It has not been decided yet whether they will take part in our experiment.

44.This one's pretty, but it costs too much.

43.This is the worst hospital I have ever seen.

42.My classmate is much cleverer than I.

41.Fred was such a hardworking student that he soon came out first in the class.

40.I knocked on his door but nobody came to answer it.

39.We have made little progress.

38.This is the worst hospital I have ever seen.

37.These goods are not up to standard.

36.A lot of natural resources in the mountain area will be exploited and used.