I agree with you that David is a clever guy,but I think he _very foolish just now.
A was B is being C has been D had been
请问选哪个,为什么啊,越详细越好,
但答案选b,我查了just now的用法,有一种情况可以用进行时,就是不明白怎么区分,你们能给出解释吗,还是答案是错的.