Hi my sweetest and respected teachers.

1 : He hit me on the nose.
(or in the nose?)
2 : I can fly <use very fast> my fingers
(on the keyboard or) over the keyboard.
(?)
3 : A friends tells me that he's going to the kitcen but after 5 minutes i saw him on the roof.how shall i say? I thought
(you are in the kicthen or) you were in the kitchen.
(?)
4 : ''The power is back'' correct?

5 : ''You beat me for that'' means?
"that" is pronoun which may stand for any thing, such as "my fault", "my behaviour.
6 : ''I have switched on the PC and it's getting on now'' correct?

7 : The video is downloading.
(or being downladed?)
8 : ''Respect others to be respected'' correct?

9 : I'm logging in to Yahoo.
(! or I'm logging in Yahoo!?)
10 : Don't go to that roof or don't go on that roof?
both correct