1.refer to 涉及；指的是

By way of illustration I'll refer to the behavior of rabbits.
我将举例说明兔子的行为。

The new law does not refer to land used for farming.
那条新法律并不涉及耕种用地。

2.because of 因为，由于

He was not a particularly good shot because of his eyesight.
他视力不好，算不上是一个出色的射手。

The man was known to the police because of previous convictions.
因为有犯罪前科，警察们都认识这个人。

3.at least 至少；最低限度

Try to eat at least four slices of bread a day.
每天尽量至少吃4片面包。

At least three British golf courses are now owned by the Japanese.
现在英国至少有3家高尔夫球场为日本人所有。

4.suppose to 认为是

There's nothing to keep us here, is there?I suppose not.
这里没有什么让我们留恋的，对吧？我想没有。

Some, I suppose, might even be in positions to influence opinion.
有的人，我认为，甚至有可能影响舆论。