could是can的过去式,它和can有两大区别。
一、can只能用于现在时态,在过去时态中用could。如:He could play the piano well when he was seven.
二、could可以用于现在时态,语气比can更婉转,如:Could you help me?
could是can的过去式,它和can有两大区别。
一、can只能用于现在时态,在过去时态中用could。如:He could play the piano well when he was seven.
二、could可以用于现在时态,语气比can更婉转,如:Could you help me?