直埋在地坪面层和墙体内的管道,分段进行水压试验并且试压工作必须在面层浇筑或封闭前进行,试验合格后土建方可继续施工。( )
参考答案:对
The dog, _____, will be made a good watchdog.
A.to train properly
B.being trained properly
C.properly to train
D.trained properly
已知圆锥的底面直径为4cm,其母线长为3cm,则它的侧面积为( )cm2.