问题补充：
I really regret to you, but at that time, I had no choice but .
A. to tell a lie; do so
B. telling a lie ; to do so
C. tell a lie; to do so
D. telling a lie; do so
答案：
A. to tell a lie; do so
(答案→)B. telling a lie ; to do so
C. tell a lie; to do so
D. telling a lie; do so
解析：此题考查动名词与不定式的区别：remember/forget/regret doing: 动作已发生
remember/forget/regret to do: 动作未发生。第一空，依照句子的意思，是对做过的事表示悔恨, 因此regret后用动名词。第二空，but前无实意动词，其后的不定式须加to, 故答案为B.
