1. The students were unable to do work without the laboratory assistant. He had to help them.
2. Your article may be published next month.
3. Computers are to free man from keeping in mind initial figures, intermediate data and final results.
4. One should turn off the light before going out.
5. Some operations for the computer must be changed and new instructions have to be added.
6. Could you speak English a year ago?
7. He was not allowed to enter the concert hall after the third bell.
8. As he received a bad mark, he had to go over the material again.
9. We shall be able to see this film in September.
10. Can you swim?
1. If she hadn't had a swollen knee, she would have played volleyball.
2. Jack will miss the football match on TV if he doesn't come home soon.
3. If I won a lot of money, I would travel around the world.
4. If he had driven carefully, the accident wouldn't have happened.
5. If I were rich, I would donate lots of money to charity.
6. If you mix red and white, you get pink.
7. Unless he leaves now, he will be late.
8. He wouldn't have banged his head if he hadn't fallen off the ladder.
9. Our team would have won if they had played better.
10. If Martha had entered the competition, she would have won a prize.
1. present simple
2.present simple
3. 1 part-present simple; 2. part-past simple
4.present simple
5. present simple