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( )。
So desperate ________ that no one could help another, each ________ to save himself and his animals.[ ]
A. was the situation; was trying
B. the situation was; trying
C. the situation was; was trying
D. was the situation; trying
在放线菌发育过程中,吸收水分和营养的器官为()
A、基质菌丝
B、气生菌丝
C、孢子丝
D、孢子