在由CH4和H2组成的混合气体中,测知碳元素的质量分数为60%,则混合气体充分燃烧生成二氧化碳和水的质量比为( )
A:11:18
B:22:9
C:1:1
D:11:27
在△ABC中,M是BC的中点,AM=1,点P在AM上且满足AP→=2PM→,则PA→·(PB→+PC→)等于( )
56-40=____
74-20=____
98-60=____
–What did you do last Sunday?–I ________ to see the movie Tai Jiong with my friend. It was really funny.