【题目】Since its start, WeChat ______into the most popular messaging communication service in China.
A. has developed B. developed
C. develops D. was developing
在线课程【答案】A
【解析】
试题分析：考查时态。本句的时间状语是since its start，自从它开始以来，“since结构”在句中作时间状语，主句通常使用现在完成时，故A正确。