把句子变为被动语态答:1,must be turned .must的意思是,一定,应该,务必.2,can't be replaced by 情态动词 +be +动词过去式.例如,must ,can.could.3,hasn't be changed 因为,the battery 是一个单数,所以,要用hasn't 4,can be received 5,could be prouduced ...
把句子变为被动语态答:1,must be turned .must的意思是,一定,应该,务必.2,can't be replaced by 情态动词 +be +动词过去式.例如,must ,can.could.3,hasn't be changed 因为,the battery 是一个单数,所以,要用hasn't 4,can be received 5,could be prouduced ...