He could swim when he was five,and l could swim,too.(使两句意思基本一致)

问题描述:

He could swim when he was five,and l could swim,too.(使两句意思基本一致)
He could swim when he was five.( ) () ()

So could I.My sister has been to Japan before(改为否定句)My sister has ( )been to Japannot