重点讲解：
1. in balance
平衡；总而言之；
eg. To keep ecology in balance is our duty.
保持生态平衡是我们的职责。
eg. Since the structures designed by civil engineers are intended to be stationary or stable, these forces must be kept in balance.
土木工程师设计的目的就是使建筑物的结构稳定，所以建筑物上的各方力都必须平衡。
2. stay away from
不去，远离（某地）；
eg. The doctor told him to stay away from fat food.
医生叫他不要吃高脂肪的食物。
eg. Flu is catching, so stay away from work.
流感是会传染的，所以别去工作了。
3. in general
总的来说；总体上来看；大体上；
eg. People in general will support us.
总体而言，人们会支持我们的。
eg. In general, I agree to what you said.
我大体上同意你所说的。
4. once in a while
偶尔；间或；
eg. Earrings need to be taken out and cleaned once in a while.
耳环要偶尔取出来清洗一下。
eg. Once in a while she phoned him.
她间或会给他打个电话。
5. for sure
无疑；肯定；
eg. No one knows for sure, of course.
当然，没人知道确切答案。
eg. For sure, we're headed for a time of abundance, at least in quantity.
毫无疑问，我们正迈向一个信息丰富（至少在数量上是这样）的时代。
