7+5=____
6+5=____
5+5=____
5+6=____
5+7=____
— I hear Susan eats little or for supper.
— It's really bad for her health. Why not exercise more to lose weight?
结合语境,解释句中加下划线的短语。
如图,在平行四边形ABCD中,点E是BC的中点,∠BOE=30°,OD=2,cos∠ADB=____ .则CD=____