— It's dangerous to swim here. Look at the sign.
— Oh, I notice it. Thanks for telling me.
A:haven't
B:won't
C:don't
D:didn't
近年来,我国迅速发展的大棚蔬菜生产,主要改变的生产条件是( )
隋朝的统治类似于上一学期学过的我国古代史上的哪一个朝代?( )
圆内接四边形ABCD,两组对边的延长线分别相交于点E、F,且∠E=40°,∠F=60°,求∠A=____ °.