Experts have been warning of the health risks caused by passive smoking
A. at a time B. at one time C. for some time D. for the time
C
解析：本题考查固定短语。从句中have been warning 可知，应用for some time 一段时间，at a time 每次；at one time 曾经。
Would you consider lying to a good friend to avoid ____ your friend’s feelings？If so, what kinds of things would you lie about?
A. hurting B. to hurt C. being hurt D. hurt