1If you are busy I'll leave you alone.
If you were busy I would leave you alone.
If you had been busy I would have left you alone.
2If my friend comes to see me I will (shall)be very glad.
If my friend came to see me I would be very glad.
If my friend had come to see me I would have been very glad.
3If he sends an e-mail we won't(shan't) worry.
If he sent an e-mail we wouldn't worry.
If he had sent an e-mail we wouldn't have worried.
1.noisy
2.quickly
3.easy
4.easily
5.careful
1) in
2) of
3) on
4) in
5) between
6) behind
7) next to