题目内容
根据句意，用括号内所给单词的适当形式填空。
76. —It’s necessary for children to learn the knowledge about road __________ (safe).
—I really agree with you. It’s very important.
77. —Invention is more useful and helpful than ________ (discover), isn’t it?
—No. They are both useful and helpful.
78. —I want to know more about Mount Tai. Could you _________ (introduce) it in detail(详细地)?
—I’d love to. But I’m afraid I have no time now.
79. —Sun Yat-sen and his men brought down the Qing dynasty during the Xinhai Revolution.
—Yes, he is the _________ (proud) of China.
80. We are all surprised that there is a __________ (suddenly) change in the plan.
