请帮我分析一下句子成分，开头的which引导的是什么成分？冒号后面的句子是不是同位语从句？谢谢啦

Which is okay,but I always wonder two things about these folks:how long did it take them to write the books they did write,and what did they do the rest of their time?

which就是主语啊，后面的is明显是谓语

冒号后面的也不是同位语从句，这里的冒号跟中文的冒号是同一个作用——引出下文，管到句号。

至于怎样是同位语从句，看图