问题
选择题
_________several times, but Mary still has no idea of how to do it properly.
A．Being shown
B．Having shown
C．Having been shown
D．I’ve shown her
答案
答案：D
此题因为题干已经有连词but，所以不能再使用分词作状语因为分词相当于状语从句，所以答案D。
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