Let's look at each of the questions to choose the correct verbs that fit the sentences:
We often never ____ to Charles, but he ____ to us.
The correct choice is c. write ... writes . This is because "We" is a plural subject, so it should be "write," and "he" is a singular subject, so it should be "writes."
I rarely ____ game shows, but my husband always ____ them.
The correct choice is a. watch ... watches . "I" is singular, so "watch" is used, and "my husband" is singular, so it should be "watches."
Jill usually ____ the newspaper in the morning. Her children ____ it at night.
The correct choice is b. reads ... read . "Jill" as a singular subject uses "reads," and "Her children" as a plural subject uses "read."
Ed ____ his windows very often. His next-door neighbors never ____ them.
The correct choice is c. cleans ... clean . "Ed" is singular and uses "cleans," while "neighbors" is plural and uses "clean."
They never ____ about us, but we ____ about them all the time.
The correct choice is a. think ... think . Both "They" and "we" are plural, so "think" is used in both cases.
For the sentence fill-ins:
"My cousin and I ____ very different. I ____ in Miami. She ____ in New York. In ____ the weekend my cousin usually ____ tennis. I ____ play tennis. I usually read at home."
The correct choice is live, live, lives . "My cousin and I live" (use "live" for plural), "I live," and "She lives."
The correct choice is work, live, lives . If "work" is the verb intended here, although "live" is more appropriate given the context.
The correct choice is On . We use "On the weekend," not "In" or "At."
The correct choice is plays, play, play . My cousin "plays" tennis, using the singular form "plays," and "I play" tennis using the singular form "play."
The correct choice is never . "I never play tennis."
All these choices ensure subject-verb agreement, which is critical in English grammar to ensure clarity and correctness in sentences.