1.It is known that 70% of the earth surface are covered with water.
正确的应该是：
It is known that 70% of the earth surface is covered with water.
把句中的are改成is,这里的is对的是"70% of the earth surface "不是复数
2.Winter is drawing near .It is becoming more colder and colder.
正确的应该是：
Winter is drawing near .It is becoming colder and colder.
把more去掉,colder and colder 是比较级,more不能修饰比较级,只有much才能修饰.
3.There are not so many books in our library than in yours.
正确的应该是：
There are not so many books in our library as in yours.
原句中than应该是比较,但是句中并没有透露出比较的成分.所以,我认为so ...as ...一样不是,翻译为在我们学校的图书馆的书和你们学校的一样不多.
4.Which of these sentences is used to saying that something is changing?
正确的应该是：
Which of these sentences is used to say that something is changing?
把saying改成say,因为to 后面加原型.
不用更改is,Which 一般是单数.
5.Write out each correcting sentence at least once.
正确的应该是：
Write out each correct sentence at least once.
把correcting改成correct,翻译成：正确的句子.
6.I am going to try going to either Montreal or Ottawa university,as they have good Physics Department.
正确的应该是：
I am going to try to go to either Montreal or Ottawa university,as they have good Physics Department.
try to是设法.
7.Mount Qumolangma is highest mountain in the world.
正确的应该是：
Mount Qumolangma is the highest mountain in the world.
在最高级前面加the,最高级前要么加the,要么加物主代词.
祝您在新的一年里,学业进步,万事如意.