Here are the answers to your questions:
There was crying baby on board.
- a) on
Will you meet me at the airport?
- c) at
The lesson starts in five minutes. Hurry up.
- d) in/up
If you miss the lessons, you will get in trouble.
- d) into
Somebody has knocked at the door. It must be my friend.
- d) at
You look taller if you stand up straight.
- b) up
We came here on foot.
- d) on
My interview is at 9 o'clock.
- c) at
Yesterday I came across children sleeping under the bridge. And I was shocked.
- c) across
Let's go to the cinema on Sunday.
- a) on
I don't read newspapers. I only looked it up.
- b) up
My son is interested in football.
- d) in
My mother is the person I can rely on.
- d) on
He usually gets to his school by bus.
- c) by
The singer was in an awful voice.
- b) in
Good luck with your exam preparation!