77.Go straight a ________the street and don’t turn left until you reach the third crossing.　

76.The children haven’t had anything to eat for over 10 hours. They must be h_____

75.The factories get the river ______(脏) than ever before and more and more fish in it　 have died one after　 another.

　 (B)根据句子意思，写出空缺处各单词的正确形式，首字母已给出。

74.One of his _______(牙)fell out when he ate something hard.

73.The children looked _______(高兴)at their teacher and asked for more stories.

72.Everyone was __________(惊奇)to hear the news that the lazy boy had passed the exam.

　 (A)根据下列句意及所给汉语注释，写出空缺处各英语单词的正确形式。

71.The computer was the most important invention in the _____(二十)century.