已知⊙O1与⊙O2是等圆,相交于A、B两点,若∠AO1B=60°,O1A=1cm,则O1O2的长是( )。
— Have you ?
— No. I had the wrong number.
A.got in
B.got away
C.got off
D.got through
DK-1型电空制动机,因空气位809线无电,所以()电空阀不能得电。