Everybody knows that … 每个人都知道……
It can be easily proved that 那是很容易证明……
It is true that ……是真实的
No one can deny that 谁也不能否认
One thing which is equally important to the above mentioned is … 跟上述同样重要的一项是…
The chief reason why 为什么……是主要原因……
We must recognize that 我们必须承认……
I am of the opinion that 我认为
This can be expressed as follows 可分为下列数点
To take …for an example … 以……为例……
Therefore we should realize that 因此我们应该了解……
We have reason to believe that 我们有理由相信……
(Now that) we know that （既然）我们知道……
what is more serious is that 更严重的是