Your grandfather looks very kind and _ to us. [ ]
A. friend
B. friendly
C. friends
答案:B
某一岩浆岩标本岩块,经表观和放大镜观察鉴别,其主要矿物成分为正长石,其次为角闪石、黑云母等,则此岩石类别为( )
A.花岗岩 B.闪长岩C.正长岩 D.辉绿岩
将盛有12mLNO2和O2混合气体的量筒倒立于水槽中,充分反应后,还剩余2mL无色气体,则原混合气体中O2的体积可能是[ ]
A.1.2mL
B.2.4mL
C.3.6mL
D.4mL