1. <u>Every</u> adult and child was willing to wait for hours until the ticket box office opened. ("Every" makes it singular, and you need "was")
2. At the entrance to the exhibition hall was a <u>crowd</u> of eager merchants.
3. Sara or <u>Mike</u> is opening the sales meeting tomorrow.
4. Either Will or his <u>agents</u> are in the office now.
5. On the shelves were several paint <u>cans</u>.
6. <u>One</u> of the workshop presenters has laryngitis.
7. Our <u>CEO</u>, along with his administrative assistant, has arrived early for the review session.
8. Carlos or the Miranda <u>sisters</u> are helping set up the audiovisual equipment.
9. The <u>government</u> publishes a great deal of printed material.
10. In this corner of our lobby stands a <u>group</u> of statues used in a promotion film.
11. <u>One</u> of my classmates was promoted at work today.
12. Our best <u>friends</u>, along with their mother, are moving to Australia.
13. The <u>family</u> has decided that it is time to have a garage sale.
14. Either lilacs or <u>lilies</u> are going to look beautiful in the arrangement.
15. Not only the oatmeal cookies but also the birthday <u>cake</u> was burned.
Collective nouns, such as <em>crowd</em>, <em>group</em>, <em>government, family</em>, normally take a singular verb in American English. In British English, collective nouns can take plural verbs.