50．Nothing is i_________ if you try your best to do it．

五、用括号内所给词的正确形式填空

49．Could you pass on the _________（消息）to Alice?

48．During the summer holidays，I saw many _________（外国人）visit the Summer Palace．

47．“What does John do in his free time?” “He c_________ animal stamps．

46．I looked for my book，but I couldn't find it a ________．

45．Do you think the experience of the astronauts in the space ship _________（令人惊异的）?

44．He didn't pass the exam，so he felt very d _________（感到失望的）．

43．I decided to work in the west of China．Do you agree with my _________（决定），Mum?

42．He was in the _________（厨房）when the UFO arrived yesterday．

41．Don't be n_________，everything is OK．