23. C) Some of the packs do not contain any manuals.

　　24. D) Solve the problem at her company's cost.

　　25. A) Ideal.

　　26. A) It is entertaining.

　　27. B) They may catch some disease.

　　28. D) Continue the feeding till it gets warm.

　　29. C) He will lie whenever he wants.

　　30. A) She made him apologize.

　　31. D) Move furniture for her.

　　32. A) The atmosphere they live in is rather unreal.

　　33. C) He has too much to know the value of things.

　　34. D) She has no time to do it herself.

　　35. B) The worship of money, beauty and pleasure.

　　36. concentrated

　　37. information

　　38. depends

　　39. straight

　　40. row

　　41. suspected

　　42. phenomenon

　　43. efficiently

　　44. Our second rule is this: it is better to study very briefly by often.

　　45. Let's say you're trying to learn new but rather difficult English vocabularies using a stack of cards.

　　46. The answer is: it is better to spread out the presentation of the words you are learning.