航天员在太空吃的食品要求高热量、高蛋白、高维生素和（）的食物。
A.少残渣、少产气体
B.低脂肪、低胆固醇
C.少水份、低刺激性
参考答案：A
— I heard the phone ringing in the office next door.
— You _______ it. They haven’t got a phone yet.
A．couldn’t hear
B．couldn’t have heard
C．didn’t hear
D．wouldn’t have heard
如何预防杏花霜冻？
