如果半径为3cm的⊙O1与半径为4cm的⊙O2内切,那么两圆的圆心距O1O2=______cm.
根据两圆内切时,圆心距等于两圆半径差,得
圆心距O1O2=4-3=1cm.
再吸收塔是和()之间建立水循环的。
A、接触塔
B、再生塔
C、解吸塔
D、汽提塔
Thank you ______ me about this. It's very kind ______ you. [ ]
A. to telling, for
B. for tell, of
C. about telling, for
D. for telling, of