1、The children were running on the playground as fast as they can.

改：can-could

解释：主句是过去进行时，从句也应该是过去时，保持一致。

2、Since her husband had died, so she had to support her family.

改：把so去掉。

解释：since表示原因，不需要so再来表示结果。两个词不能同时用在一个句子中。

3、He won't go out until his mother will come.

改：will come-comes

解释：主句是一般将来时，until引导的时间状语从句用现在时表示将来，改为第三人称单数。

4、He was very foolish that he didn't pass such an easy exam.

改：very-so

解释：so...that，如此……以至于。

5、Tom had gone out as soon as his mother got home.

改：had gone-gone

解释：主句用一般过去时。

6、It was three months since he came to our school.

改：was-is

解释：从过去到现在的一段时间，用现在时。

7、The platground of our school is larger than their school.

改：加上 that of (their school)。

解释：操场要和操场作比较，不是跟学校比。用that来指代。

8、The streets in Nanjing are wider than Shanghai.

改：those in (Shanghai)。

解释：街道要和街道比较。用those来指代复数的名词。

①打招呼，问好

Good morning? Good morning! 早上好?早上好!

How old are you? I am (four). 你几岁了?我(四)岁。

Are you OK? Yes, I am OK. 你还好吗? 我挺好的。

②表扬，感谢

You are clever! 你真聪明!

Happy New Year! 新年快乐!

Miss Li, you are very beautiful! 李老师你真漂亮!

Thank you very much! 非常感谢你!

③道歉

I am sorry. 对不起。

Never mind. 没关系。

A son never thinks his mother ugly,and a dog never shuns its owner’s home however shabby it is.儿不嫌母丑，狗不嫌家贫。

The frog in the well knows nothing of the great ocean. 井底之蛙，不知大海。

The fox may grow grey, but never good. 狐狸毛色可变灰，但是本性难移。

When the fox says he is a vegetarian, it’s time for the hen to look out. 狐狸说它吃素的时候，母鸡就得注意。

A speck of mouse dung will spoil a whole pot of porridge. 一粒老鼠屎，坏了一锅粥。