It when I my homework last night. ( )
A:raining, did
B:rained, was doing
C:was raining, do
D:rains, was doing
如图,已知AB是⊙O的直径,M,N分别是AO,BO的中点,CM⊥AB,DN⊥AB.求证: AC^=BD^ .
下列各句中,没有语病的一句是( )