Mr. Smith used to smoke ________ but he has given it up recently.
选择一项：
a. roughly
b. completely
c. heavily 解析：【译文】史密斯先生过去抽烟很多，但最近已经戒烟了。本题考查词义辨析。immediately意为“立即”；roughly意为“大约，大致”；heavily意为“大量地”；completely意为“完全地”。由题意可知，C项意思最恰当。
d. immediately