30. According to a recent survey of many bookstores, books on popular science are ______. 　　　

A. in demand　 　　　　　　 B. in need　 　　　　 C. in charge　 　　　　　　　　　　 D. in control

29. With the economic crisis it is ________ difficult for a university graduate to find a job today.

　　　 A. similarly　 　　　　　　　 B. equally　 　　　　　 C. increasingly 　　　　　　 D. possibly　

28. This type of camera will help you take perfect pictures however ______ the conditions are.

A. demanding　 　　　　　 B. dangerous　 　　　 C. extraordinary　 　　　　 D. different　

27. It might seem dull, but using repetition is a good way for teachers to ______ the message ______.

　　　 A. hand…over 　　　　　　 B. let… out 　　　　　 C. get… across 　　　　　　 D. give… away