Как выбрать правильную форму сослагательного наклонения (см.)?

Ex. XIX. Open the brackets and use the correct form of the subjunctive mood.

1. She was breathing heavily as if she (run) a long distance.
2. It seemed as though he (know) it long ago.
3. She looked at him as if she (see) a ghost.
4. He looked as if he (want) to say something but (be) afraid to begin his speech.
5. She behaved as though nothing (happen).
6. It seemed as if he never (hear) of it before.
7. They met as though they (see) each other for the first time.
8. They talked as if they never (meet) before. 9. They talked as if they (know) each other for ever so many years and it (not be) the first time they met.
9. He nodded slowly as if he (agree) to her suggestion but she knew he would never do it.
10. Her eyes were swollen and had shadows as if she (not sleep).
11. They stared at eachother in silence, and it was as if they (listen) for distant footsteps.
12. He speaks French as if he (be) a Frenchman.

14.Nothing had changed in the room but it seemed as though somebody (be) there.

1. She looked very tired as if she (work) from early morning till late at night.