2.并列句中的省略

(1)一般说来，在后一并列句中凡是与上文相同的成分通常都会被省略。

To some smile is very easy，and to others(smile is)so hard．

对有些人来说微笑很容易做到，而对其他人来说就难了。

They are being used everywhere—sometimes(they are being used)where they shouldn't(be used)．(人教大纲版高一上第59页)

它们的应用无处不在，有时还用在了不该用的地方。

When Spielberg was young，his dream was to go to the Film Academy，but he couldn't(go to the Film Academy)．(人教大纲版高一上第31页)

斯皮尔伯格小时候曾梦想上电影学院，但未能如愿。

(2)简单句的并列结构中也常有省略的做法。

We may go there by train or(by)air．

我们可以坐火车或乘飞机去。