单选题 The Constitution"s vague nature has given it the flexibility to be adapted when circumstances change.
【正确答案】 A
【答案解析】vague：模糊；两可。imprecise：不确切，不明确。这两个词意思相近。apparent：清楚。It is apparent that we have made a mistake.显然，我们犯了个错误。clear：清楚。easy：容易。