例句：
This will be a problem for some time to come.
這將是未來一段時期裏的一個問題。
This is the one major drawback of the new system.
這是新系統的`一大弊端。
This is one of the most commonly used methods.
這是最常採用的方法之一。
It's about this high.
大約有這麼高。
The number of new students decreased from 210 to 160 this year.
今年新生人數從210減少到160。
