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

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”。