39. Let’s learn to use the problem we are facing _______ a stepping-stone to future success.

38. I think Jim is the right man for the job. He is hard-working, smart, and _______ kind-hearted.

33. The medicine works more effectively _______ you drink some hot water after taking it.

29. He told us that the girl was _______, so we went to save her.

28. Vitamin D helps our bodies make a special chemical, and this special chemical,        _______, affects our brains, making us feel happy.

22. Careful surveys have showed that audience _______ teachers and students are more likely to take seats _______ directed.

29. ______ many people, he prefers classical music to pop.

---Would you like some more beef?
---No, thanks. I’m ______ a diet.

17．--- Mary, I have got a new cell phone number!
--- Oh, hold on. I’ll put it down just___________ .

13．Many medical scientists are racing__________time to find a cure for H1N1 as soon as possible.