它们的时代到来了，它们成了这个行星上最重要的动物。

When it was in my turn，I was too excited to speak.

译：

归纳拓展：

in turn依次；轮流；因此；因而 by turns轮流；依次

take turns to do sth./in doing sth.轮流做某事

It is sb.'s turn to do sth.轮到某人做某事

The girls' names were called out in turn. 译：

小试牛刀： 介词填空

①They should take turns_____ ___looking after their old mother.

②The new couple of lovers did housework______ __ turns.

9．prevent...from...阻止，制止

They are putting too much carbon dioxide into the atmosphere，which prevents heat from escaping from the earth into space.(P26)

他们把过多的二氧化碳释放到大气层中，这使得地球上的热不能释放到太空中去。

归纳拓展：

prevent /stop/ keep+ +宾语+from doing 阻止......干某事

protect...from(against)．..保护......不受......侵袭(from后接能带来伤害或损害之物)

【提示】其中keep后的from不可省 ，prevent /stop后from可省　，用于被动语态中时，三个短语from都不能省略。）

小试牛刀： 单句改错

①Nothing could prevent him to go out even though it's bad weather.______________

②The plan can be prevented being carried out. _________________

③他们没有阻止他发表自己的观点。

译：_____________________________________________

10．So whether life will continue on the earth for millions of years to come will depend on whether this problem can be solved.(P26) 所以，在未来的数百万年中，生命能否在地球上延续取决于这个问题能否得到解决。

此句为主从复合句。句中两个whether分别引导了两个名词性从句，分别在句中作主语及介词on的宾语。