霍乱大流行最重要的传播形式是（）
A.食物污染
B.苍蝇传播
C.接触患者
D.水源污染
E.接触带菌者
参考答案：D
Vehicle designers are well aware that they need to ______ the idea of cars that have a low environmental impact.
A．end up with
B．put up with
C．keep up with
D．come up with
下列哪项是人类同种异型抗原？（）
A.病毒
B.动物血清
C.细菌
D.HLA
E.花粉
