A:一定是化合物
B:可能是单质,也可能是化合物
C:一定是单质
D:一定是同素异形体
关于蛔虫病的预防,下列叙述错误的是( )
——Have you seen ________ film Where are We Going, Dad?——Yes, it's ________ interesting film!
已知α为钝角,β为锐角,且sinα=45,sinβ=1213,则cosα-β2的值为( )
I brush my teeth and wash my face. ____
I go to school.____
What do you do after breakfast? ____
I go to school on foot. ____
What do you do before breakfast? ____
How do you go to school? ____