道路被封闭了，因为已经下了一整夜的大雪。
The roads were closed because it had been snowing heavily all night.
▼点击显示答案
had英 /hæd/|美 /hæd/
been英 /biːn/|美 /bɪn/
snowing英 /ˈsnəʊɪŋ/|美 /ˈsnoʊɪŋ/
解释
had been snowing 是过去完成进行时，表示下雪这个动作从夜间开始，一直持续到道路被封闭的时候。
The roads were closed because it had been snowing heavily all night.
had been snowing 是过去完成进行时，表示下雪这个动作从夜间开始，一直持续到道路被封闭的时候。