31. The doctor would allow him to go home _______ he remained in bed.
A. as though B. for fear that C. on condition that D. as far as
32. The driver can adjust the heating in winter and the air conditioning in summer to suit his own _______.
A. reference B. preference C. convenience D. selection
33. They moved to Portland in 1998 and lived in a big house, ______ to the south.
A. the windows of which opened B. the windows of which is opened
C. its windows opened D. the windows of which opening
34. I was annoyed by my friend who came late for our appointment but did not bother to ask how long I _______.
A. waited B. was waiting
C. have waited D. had been waiting
35. _____ for a certain period of time, the moving parts of the car engines were worn out.
A. Having been used B. Having used
C. To be used D. Used
36. The manager promised to keep me _____ of how our business was going on.
A. to be informed B. on informing
C. informed D. informing
37. The best way to make a kid be independent is to put him in a position _____ he has no one else to ask for help.
A. that B. what C. where D. which