A. It's very hot.
B. Three little pigs are fat.
C.I have a good idea.
D. Open the door.
E. We are good brothers.
如图,A,B是直线l同侧的两点,作点A关于直线l的对称点A′,连结A′B.若点A,B到直线l的距离分别为2和3,则线段AB与A′B之间的数量关系是( )
下列不属于生命现象的是( )
H2(g)+I2(g)⇌2HI(g)(正反应放热),反应经过5分钟测得碘化氢的浓度
为0.5mol/L,碘蒸气的浓度为0.25mol/L.请填写以下的空白: