【题目】— Can I call you back at two o'clock this afternoon?
— I'm sorry, but by then I ____ to Beijing. How about five?
A.fly
B.will fly
C.will be flying
D.am flying

【答案】C
【解析】句意：——你能在今天下午两点回电话吗？——对不起，那时我将要飞往北京，五点如何?根据by then可知用将来进行时，故选C项。