He went to school ___he___seven years __ 同义句!如上!

问题描述:

He went to school ___he___seven years __ 同义句!
如上!

when/since he was seven years old at the age of seven

He went to school when he was seven years old
同义句:he went to school at the age of seven

when was old
he went to school when he was seven

是填空还是怎样呀?有点不明白呀
He went to school when he was seven years old