托福 作文开头套句：
When it comes to...， some think...
There is a public debate today that...
A is a common way of...， but is it a wise one?
Recently the problem has been broughtsintosfocus.
提出观点：
Now there is a growing awareness that...
It is time we explore the truth of...
Nowhere in history has the issue been more visible.
进一步提出观点：
...but that is the only part of the history.
Another equally important aspect is...
A is but one of the many effects. Another is...
Besides， other reasons are...
提出假想例子的方式：
Suppose
