【错误表达】

She acts as though she is mad.

她好像疯了一样。

【讲解辨析】

As though引导的从句要使用虚拟语气。句中主句是she acts，主句中用的是一般现在时，那么从句就要使用一般过去时，is改为were。如果主句用的是一般过去时，从句就要用过去完成时。例如：I felt she had touched me. 我觉得她好像碰了我一下。

【正确表达】

She acts as though she were mad.

【举一反三】

She remained cool-hearted as though nothing had happened.

她仍然很冷静，好像什么事情都没有发生一样。