Of the two brothers, Bill is younger one, and he is a quiet boy, that most adults like

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

(答案→)A. the; oneB. a; the oneC. a; oneD. the; the one解析：考查冠词和代词用法。第一空填the，特指Bill是两者当中较年轻的那个。第二空的one与a quiet boy构成同位语关系，因为a quiet boy是泛指，那么one也应该是泛指。句意：在两兄弟中，Bill是较为年轻的那个。他是一个安静的男孩，一个大部分的成年人都喜欢的一个男孩。故A正确。

谢谢了