从A、B、C、D选项中，选出可以填入空白处的最佳选项，并在答题卷上将该项涂黑。
16. Paper money was in _________ use in China when Marco Polo visited the country in _________13th century.
A. the, / B. the , the C. /, the D. /, /
17. Waiter: Here is the steak you ordered. Please _________and enjoy yourself.
Customer: Thank you.
A. take it easy B. take your time C. take your food D. go right ahead
