英语口语四级必背句？

The reason why we have to grow trees is that they can supply fresh air for us.

我们必须种树的原因是它们能供应我们新鲜的空气。

Finished labours are pleasant.

完成工作是一乐。

Have you somewhat to do tomorrow,do it today.

明天如有事，今天就去做。

The sum of behaviour is to retain a man's own dignity, without intruding upon the liberty of others.

人的行为准则是，维护自己的尊严，不妨碍他人的自由。