根据括号里的中文提示，完成句子；每空填一个单词。
71. When she saw the poor dead cat, she ______ _______ _______.(禁不住哭了)
72.Though pandas eat vegetables sometimes, they mainly ______ ______ bamboo.(以…… 为主食)
73. The earthquake will ______ ______ a lot of diseases and homeless people.（导致）
74. It is ______ ______ _______ _______ arguing with him; he is always not reasonable.（浪费时间）
75. Don’t ______ ______ _______ your classmates. It is impolite.（取笑）
76. He didn’t steal anything. ______ ______ he is honest all the time.（事实上）
77. After eight years, the machine is still _____ ______ and in good condition.（在使用中）
78. Once you make a promise, you should ______ it ______.（实施）
79. We had reached the top of the mountain ______ _____ _____ sun rose.（到…… 时候）
80. You must keep calm when fires ______ ______ . （发生）
