根据生态学原理，要使能量在食物链传递时损失最小，人类应采取的食物结构是( )
A．喝牛奶、吃牛肉 B．禽蛋C．水产 D．谷物
参考答案：D
Paul and I ______ tennis yesterday. He did much better than I. [ ]
A. play
B. will play
C. played
D. are playing
既能敛汗，又能补肾宁心安神的药物（）
A.酸枣仁
B.五味子
C.浮小麦
D.牡蛎
E.龙骨
