Answer:
The sheep is/are/was/were/will be grazing.
Step-by-step explanation:
There can be multiple answers for the black in the given sentence. And depending on the noun and the tense, we can give the answer as below-
1. Singular noun "sheep":
a. "is grazing" for present continuous tense
b. "was grazing" for past continuous tense
c. "will be grazing" for future continuous tense
d. "has been grazing" for present perfect continuous tense.
2. Plural noun "sheep":
a. "are grazing" for present continuous tense.
b. "were grazing" for past continuous tense
c. "will be grazing" for future continuous tense
d. "have been grazing" for present perfect continuous tense.
But in all cases, the noun "sheep" remains the same in spelling whether it be singular or plural because the plural of "sheep" is still "sheep". And there are more tense forms that can be used but the above are some of the common ones.