I’m afraid that if you 've lost it ,you must payfor it. 这句话的宾语从句中含有主从复合句

问题描述:

I’m afraid that if you 've lost it ,you must payfor it. 这句话的宾语从句中含有主从复合句
可是哪个是主句,哪个是从句(宾语从句中的)

that后面为宾语从句,在宾语从句中,
you must payfor it 主语
if you 've lost it 从句1那谓语呢? 2 you must payfor it是 主句吧是谓语还是must 是谓语还是must payfor it 是谓语。谓语必须只有动词吗