pay for ...是为.付款的意思.原句的意思是,你必须在走之前为我替你做的事付款.
what引导宾语从句,在前面一句中做pay for的宾语,在后面一句中做done的宾语.
how much does it cost?意思是它要多少钱?spend,pay for 后面一定要接宾语,cost不需要.
pay for ...是为.付款的意思.原句的意思是,你必须在走之前为我替你做的事付款.
what引导宾语从句,在前面一句中做pay for的宾语,在后面一句中做done的宾语.
how much does it cost?意思是它要多少钱?spend,pay for 后面一定要接宾语,cost不需要.