Delivery is free ______ charge if goods are paid for in advance .

Delivery is free ______ charge if goods are paid for in advance .

A.from

B.in

C.of

D.at

答案及解析： C

解析：

英语是介词的语言，请在平时阅读与聆听时，注意观察语篇中所有介词的使用规律，特别注意介词于其他词类的搭配关系。如：be good at / interested in / fond of / different from 等等。