已知两圆的半径分别为3和4,圆心距为5,则这两圆的位置关系是______
相交
∵4-3<5<3+4,∴根据圆心距与半径之间的数量关系可知⊙O1与⊙O2的位置关系是相交
— Has Tom finished his homework yet?
— I have no idea, he _____ it this morning.
A.was doing
B.did
C.had done
D.would do
某井没有系统试井资料,但已知周围同层的几口生产井的合理压差都为静压的60%左右,试求该井的合理压差。