朋友,我来回答,我六级过了,564分.
The only vacant apartment （I have） is 600 dollars.里面的I have去掉后是完整的,这里,翻译为“我租用的”,修饰apartment.这里的Ihave到底算完整句,是主谓结构完整,因为他省略了that,因为that作定语从句的宾语时可以省,The only vacant apartment （that）I have is 600 dollars