could have done 本可以做而没有做,能做而没有做 shuld have done 1.本应该做而没有做；2.猜测 1.You could have won the first prize if you have spent more time on it. 2.The ground is wet.It should have rained last night. 3.It's 8 o'clcok.I am very hungry.You should have cooked the dinner.
