问题补充:
all of you are top students, only one will be chosen for the coming competition.
A. While
B. Since
C. If
D. As
答案:
(答案→)A. While
B. Since
C. If
D. As
解析:句意:尽管你们都是很优秀的学生,但是将只有一个学生将被选出来参加竞赛。While:尽管,当...时候 Since:既然,因为 If:是否 As:由于,随着。句意前后有转折关系,所以用while引导让步状语从句。故选A。