哪种临床表现对诊断急性肾炎最有意义（）
A.水肿
B.血尿
C.高血压
D.尿比重减低
E.中等量以上的蛋白尿
参考答案：B
More has been learned about the Moon than any other of the Earth's neighbors in space because of the Apollo program, which enabled men to walk on the Moon and bring back hundreds of pounds of________.
A．rocks
B．rock
C．stone
D．stones
回烧总是在混合气体从焊嘴喷出的速度（）其燃烧的速度时发生。
A.大于
B.等于
C.小于
