如图所示,CD∥AB,OE平分∠AOD,OF⊥OE,∠D=50°,则∠BOF为( )
A:35°
B:30°
C:25°
D:20°
按要求,写单词。
many(最高级)____
-What are you doing?
-I'm s____ the floor. It's dirty.
人类活动使环境的恶化越来越严重,下列关于酸雨的叙述,不正确的是( )