问题补充：
-
-Not bad.
A. How far is it?
B. Whats he doing?
C. Hows it going?
D. Where is he going?
答案：
A. How far is it?
B. Whats he doing?
(答案→)C. Hows it going?
D. Where is he going?
解析：句意：---进展得怎么样？---不差。A. How far is it?多远？B. Whats he doing?他正在干什么？C. Hows it going?进展得怎么样？D. Where is he going?他去哪？根据题意，故选C。
