How does Roger straddle the line between civilization and savagery? LOTF question

It is very important to promote self esteem in young children

Which sentence about subject-verb agreement is not true? a. singular subjects go with singular verbs. b. plural subjects go with plural verbs. c. when the subject and the verb go together, they agree. d. plural verbs go with singular subjects.

Why does the host answer the guest with brief responses during the party?