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 knife has been sharpened.
The knives have been sharpened.
The reef attracts tourists.
The reefs attract tourists.
The thief will be caught.
The thieves will be caught.
1. The leaf has turned red.
2. The fife had the solo.
3. The calf is hungry.
4. The scarf kept him warm.
5. The knife will be useful.
6. The giraffe was eating leaves.
7. The cliff is being explored by geologists.
8. The wolf howls every night.
9. The loaf is rising.
10. The chief will decide.
11. The shelf is being used.
12. The proof is convincing.