Question

—— Is Tom still smoking ?

—— No.By next Saturday he ＿＿＿＿＿＿＿ for a whole month without smoking a single cigarette.

A.will go     B.will have gone  C.will have been     D.has been going

Answer 1

B

解析:

by 后跟将来的时间状语时，主句要用将来完成时。go without 意为“在缺……的情况下对付”。