体循环和肺循环的共同规律是 [ ]
A.心房→静脉→器官→动脉→心室
B.心房→动脉→器官→静脉→心室
C.心室→动脉→器官→动脉→心房
D.心室→动脉→器官→静脉→心房
答案:D
In Suzhou it doesn't often _____________ in winter, but it is _____________ in summer. [ ]
A. snowy, rainy
B. snow, rains
C. snow, rainy
D. snowy, rains
一辆汽车4小时行驶104千米,照这样计算,从甲地去乙地行了6小时,甲乙两地相距多少千米?(用比例解)