The train at the present speed until it reaches Beijing at about 6 :30 am.
A. went
B. has gone
C. goes
D. will be going
网友回答
A. went
B. has gone
C. goes
(答案→)D. will be going
解析：句意：火车将以现在这个速度行驶，直到大约九点钟到达山脚为止。until引导的句子用了一般现在时，说明主句要用将来时态，再根据时间状语at the present，所以用将来进行时。