He balanced the attraction of a high salary against the prospect of working long hours.

参考译文：她对高薪和长工时两者的利弊作了权衡比较。

翻译：他对高工资和长工时两者足了权衡比较。

balance against  和 ... 保持平衡

Income and payment must be balanced against each other.
收支必须保持平衡。

(1)against   prep.和…对比；对照 (英文解释：If something is measured or valued against something else, it is measured or valued by comparing it with the other thing.）

You must weigh the benefits against the cost.
你一定要权衡利益与成本二者的得失。

Our policy has to be judged against a clear test: will it improve the standard of education?.

对我们的政策作出评判必须根据一条明确的准则：它是否会提高教育的水准？

 Check the operator's productivity against agreed targets.

根据既定目标检验操作员的效率。

(2)prospect    n.（尤指事业的）成功机会，前景，前途(英文解释： Someone's prospects are their chances of being successful, especially in their career.）

I chose to work abroad to improve my career prospects.  

我选择出国工作以求在事业上有更好的发展。

a detailed review of the company's prospects.  

对该公司前景的详细考查。