问题：
[单选题]据调查,如果我们的林业工作得不到改善,东北的森林地区在十到二十年内就会完全枯竭。()
A
According to a survey, the forested region in the northeast will be depleted completely in ten to twenty years, unless our forestry work is improved.
B
According to a survey, unless our forestry work is improved, in ten to twenty years the forested region in the northeast will be depleted completely.
