21. By tradition, on __________ Independence Day, Americans play sports, have barbecues and hold parties throughout __________ day to celebrate this festival.
A. the, the B. a, the C. the, a D. /, the
22. It’s the __________ in the west to open a present when someone gives __________ to you.
A. custom, one B. habit, one C. bobby, it D. favour, it