Английский язык, не очень понимаю это некоторые предложение в этом задании

14. Раскройте скобки и поставьте глагол в нужную форму.

1. If they (used) a new method, the results of the experiment would be different.

2. If we have any problem with the equipment after start-up, we (will invite) a

representative of your company.

3. If you know the dimensions of the body you (will calculate) easily its volume.

4. If the student had known the specific heat and the weight of the substance, he (would have calculated) its thermal capacity.

5. If cars (were) more efficient we would use less fuel.

6. If they (had applied) the new technology, the productivity would have risen.

7. A number of important innovations would have been impossible unless

new surface finish technology (had been used).

8. If electric motors (were used), cars would not pollute the air.

9. The product quality (would improve) if latest innovations and techniques were used.

10. We (would have invested) our money well if we had bought that machine.

11. Unless the temperature rises, the speed of molecules (won't increase).

12. If I were you, I (would ask) a lawyer for some advice.

13. If the code number of spare parts had been entered correctly the company (would have supplied) everything in time.

14. If the machine (breaks) down within the guarantee period, it will be replaced free of charge.