21. Of the two brothers, Bill is ______ younger one, and he is a quiet boy, ______ that most adults like very much.
A. the; one B. a ; the one C. a; one D. the ; the one
22. In 1942, Columbus and his crew arrived ________ was so-called the New World by the westerners.
A. what B. in which C. where D. in what
23. The soldier raised his gun and calmly ______ it at the enemy commander, fired.
A. aiming B. aimed C. to aim D. aim
