急、英语 Noise pollution was a problem before the ---- (close)of

问题描述：

急、英语 Noise pollution was a problem before the ____ (close)of the old airport
Noise pollution was a problem before the ____ (close)of the old airport.
答案应该是closing ,但我写的是closed
请说明下理由、

1个回答分类：英语 2014-09-30