a.  模棱两可的；不明确的 ≠ unambiguous

• ambiguity

  n.  模棱两可；不明确（的事物）[+ in]

• legal ambiguities  法律上含混不清的地方

• Here the Stockholm declaration is ambiguous. 宣言中说得比较模糊

• What is the attitude of most researchers towards making their own data public?

  态度不明确

  A) Opposed.  B) Ambiguous.  

• The language in the Minister’s statement is highly ambiguous. 部长的声明措辞很含糊。

• There was an element of ambiguity in the president’s reply. 总统的回答有点模棱两可。

BrE /æmˈbɪɡjuəs/

NAmE /æmˈbɪɡjuəs/