Can anyone help tell me if these are correct?
Subject-verb agreement A
1a. Did you know a famous animal-rights activist has criticized horseracing because of the dangers involved? 1b. Did you know a famous animal-rights activist have criticized horseracing because of the dangers involved
Subject-verb agreement B
2a. Peer editing academic papers require critical-thinking skills and diplomacy.
2b. Peer editing academic papers requires critical-thinking skills and diplomacy.
Subject-verb agreement A
3a. Vitamins that are sold in a health-food store are not regulated by the Food and Drug Administration.
3b. Vitamins that are sold in a health-food store is not regulated by the Food and Drug Administration.
7a. I was interested in working on the presidential campaign if the opportunity still exists.
7b. I am interested in working on the presidential campaign if the opportunity still exists.
Verb form and verb tense B
8a. Since American Idol premiered on television, many talented contestants have appeared on the show.
8b. Since American Idol premiered on television, many talented contestants appeared on the show.
Verb form and verb tense A
9a. The ancient Egyptians built pyramids as burial sites for their leaders.
9b. The ancient Egyptians have built pyramids as burial sites for their leaders.
Identifying antecedents A