中国大学MOOC: Which of the following payment terms are usually accepted for duty-free sale on board?
                    举一反三
- Which of the following payment terms are usually accepted for duty-free sale on board? A: traveler’s check B: cash C: cheque D: credit card
 - 中国大学MOOC: The duty in duty-free refers to________ .
 - Which of the following expressions are demanding favorable terms of payment?
 - Which of the following terms are usually associated with the Internet?
 - 中国大学MOOC: Which of the following solar terms is in Winter?
 
