n/could have done表示无虚拟解释为过去能够做时,若后面是过去式,则要用can还是could?还是两个均可?
n/could have done表示的是虚拟,解释为本可以做,但没做时,若后面为过去式,是用can还是could ?若为一般现在式呢?
eg。
I ____have arrived on time,but my bike was
broken 。
I ____have arrived on time,but my bike is
broken 。
。