—Excuse me. Where is the museum?—It is quite far. It will take you half hour to go there

—Excuse me. Where is the museum?
—It is quite far. It will take you half hour to go there by bus.
A. an; /
B. an; a
C. a; /
D. /; /

(答案→)A. an; /B. an; aC. a; /D. /; /解析：句意：打扰了，请问博物馆在哪儿？——相当远。乘公交车到那儿大约得花你半个小时的时间。结合语境可知前一空表示数量1个小时，故用不定冠词。Hour词首音素是元音，故不定冠词用an，下文bus在本句中by后面在接交通工具做交通方式时，交通工具前不加冠词。故选A。

我学会了