问题补充:
The train at present speed until it reaches Beijing.
A. is running
B. will be running
C. will have run
D. has run
答案:
A. is running
(答案→)B. will be running
C. will have run
D. has run
解析:考查时态。句意:火车将以目前的速度运行直到抵达北京。结合语境可知本句描述的接下来正在进行的动作,故用将来进行时态,选B。