How were the Chinese people able to privatize the housing sector so quickly? 请语法高手解释be to do

题目

How were the Chinese people able to privatize the housing sector so quickly? 请语法高手解释be to do
请语法高手详细解释 be to do 的用法,以及其和 can,be able to 之间的异同?谢谢

答案

can 情态动词,
但表示"能够"时,
can,be able to 通常是差不多的.
差别在于"be able to "可以用于各种时态.
be to do 这是一种将来时,表示"最近"或"注定会发生的" 将来的事情.