I could fly kites seven years ago.(seven years ago,七年前是指过去,所以用过去时,can的过去时为could.)
Did you see him just now?(过去时中助动词do,does时变为did,后面接动词原形.)
变陈述句:I saw him just now.
I could fly kites seven years ago.(seven years ago,七年前是指过去,所以用过去时,can的过去时为could.)
Did you see him just now?(过去时中助动词do,does时变为did,后面接动词原形.)
变陈述句:I saw him just now.