i think______(一定是）Jack that parked the car like that,for he is al_英语解答

i think______(一定是）Jack that parked the car like that,for he is always doing so.
为什么标答是it must have been

人气：104 ℃　时间：2019-08-18 04:13:16

解答

it 是形式主语,代后面的从句,原来形式是it must be,用了完成时为什么要用完成时后面是parked