about后面接事情或物品（即sth），这里表示因某事物而高兴。
with后面既可接人又可接物，用法更宽泛。
about：prep.关于;对于;目的是;为了;涉及…方面;忙于;从事于。
with：prep.具有;和;用;有;以;跟;同;带有;使用;和…在一起;借。
扩展资料
There was much discussion about the reasons for the failure.
就失败的`原因进行了大量的讨论。
She moves with the natural grace of a ballerina.
她的动作具有芭蕾舞演员自然优雅的丰姿。
There are still a few residual problems with the computer program.
电脑程序还有一些残留问题。
It was a difficult situation, when you think about it.
仔细想来，当时处境是很困难的。
The population is increasing at about 6% per year.
人口以每年约6%的速度增加。
