change into plural / Exercise 7

For each of the following sentences, change the subject of the verb to the plural, and change the verb so that it agrees with its subject. For example:
The hypothesis is still tentative.
The hypotheses are still tentative.

The nebula has been studied by many scientists.
The nebulae have been studied by many scientists.

The thesis will have been reviewed by experts.
The theses will have been reviewed by experts.

1. The synopsis is accurate.
2. The phenomenon surprised us.
3. The stratum contains fossils.
4. The analysis was proved correct.
5. The crisis has caused concern.
6. The spectrum includes many different colors of light.
7. The axis of rotation will be investigated.
8. The stimulus has been found to be effective.
9. The criterion was used to judge which proposals should be accepted.
10. The oasis is visited by many travelers.
11. The honorarium is being presented today.
12. The parenthesis was omitted.