What's wrong with your eye? It looks red.
What's the   with your eye? It looks red.
We need the money to carry on with our work.
We need the money to   our work.
I've bought a few key rings for my classmates.
I've bought a   of key rings for my classmates.
The boy cut in at the head of the queue.
The boy   in at the head of the queue.
Pollution is becoming more serious. so it's time for us to go green.
Pollution is becoming more serious, so it's time for us to protect the   ．