单选题 ______ you transfer your account, sign on the dotted line.

A、 (A) While
B、 (B) Because
C、 (C) During
D、 (D) Before

【正确答案】 D

【答案解析】Before indicates a sequential time relationship. Choice (A) indicates a simultaneous time relationship. Choice (B) indicates cause and effect. Choice (C) indicates a simultaneous time relationship but is not followed by a subject and verb.