叶菜类是指以肥嫩菜叶、叶球为主要食用部分的蔬菜。
参考答案：错
设集合P={x|x2+x-6=0}，则集合P的元素个数是（ ）
A．0
B．1
C．2
D．3
I don’t know why he is late.
—Nor do I.He__________an accident.
A．could have had
B．should have had
C．might have had
D．must have had
