I have two good friends.They are Tom and Mike.I am shorter than Tom,and Tom is shorter than

I have two good friends.They are Tom and Mike.I am shorter than Tom,and Tom is shorter than
Mike.We all like playing football,but I am better at it than Tom,and Tom is better at it than Mike.(这段文章中的“We all like playing football,”all前面为什么不能加are呢?为什么比较级前能加be动词?)
另一道：Sometimes people play games inside the room.Sometimes they play outside.We can ( )sports here and there.
A:look B:find C:talk D:say （答案选的是B，而我选的是A，为什么我选的不对？翻译……）