小学英语选择题：The sun is ____ bigger than the moon.

The sun is _A_ bigger than the moon.

这是主系表结构，主语是the sun，系动词（即am is are)是is,表语是后边的bigger than the moon.和the sun is big.是一个道理，不过用了比较级。
如果再分细的话，than是个介词，the moon做介宾，much是副词做状语，修饰bigger

A

A

C