a)
1. A lot of goods may be bought and sold from each other by merchants.
2. Two contacts were managed to made by him at the beginning of the year.
3. The value is measured by you in terms of money.
4. Money may be kept by you as long as you wish.
5. A new branch will be opened by them at they end of the month.

b)
1. They asked him to sign the contract.
2. Russian government pays great attention to the chemical industry.
3. Several reports followed this lecture.
4. The state will own and operate the new farmland.
5. All of his fellow-workers spoke well of him.