this is the first time when we have been to china错在哪

the first time .that 可以看做一个固定句型,其中that可以省略.不可以用when,因为后面的句子成分完整.--------------------------------------------------over---------------------------------------------------...你能讲讲为什么吗你看一下when后面那个句子：we have been to china.主语we ， 谓语 have been to ，宾语china。整个句子成分完整不需要用when 引导一个定语从句来修饰thefirsttime。而且，用the first time做先行词一般常用的引导词是that 或者不加引导词，这是定语从句中的法则。-----------------------------------------------------over--------------------------------------------------------------