Question

4．飞机起飞前，乘务员的职责之一就是确保所有乘客都系好安全带．（ensure）Before the plane takes off，one of the flight attendants duties is to ensure that all the passengers have fastened their safety belts．．

Answer 1

分析 Before the plane takes off，one of the flight attendants duties is to ensure that all the passengers have fastened their safety belts．

解答 Before the plane takes off，one of the flight attendants duties is to ensure that all the passengers have fastened their safety belts．
这是描述的乘务员的基本职责，所以用一般现在时．
本句可用before引导一个时间状语从句，主句中用动词不定式作表语，that又引导一个宾语从句，作动词ensure的宾语．take off起飞，fastened one's safety belts系好某人的安全带．

点评 主从复合句的运用能够更生动形象的表达出句子的意思，同时也能够将英语句式的表达提升到一个新的高度，所以对于复杂句式及非谓语动词的练习与运用还需要进一步加强．