all of them are strong candidates, only one will be chosen for the post.
A. Since
B. As
C. If
D. While
网友回答
A. Since
B. As
C. If
(答案→)D. While
解析：连词辨析。A. Since “既然”表原因 B. As “因为、当…时候、虽然”作虽然讲时要用倒装语序 C. If 如果 D. While 虽然 虽然他们都是强有力的竞争者但是这个岗位只选一个人。 根据句意选D