以下哪个与膨胀水箱连接的管路要设阀门:()。
A.膨胀管
B.循环管
C.信号管
D.溢流管
参考答案:C
下列属于生物的是[ ]
A.恐龙骨骼
B.木马
C.小草
D.钟乳石
—Allan looks tired out.
—Sure. He in the gym for two hours.
A.works out
B.had worked out
C.has been working out
D.was working out