Grammar error questions

Question

Find the error, correct it, and explain why it is an error.

1. Will he goes to the lake with us on Saturday?

I know the error is “goes" and the sentence should be Will he go to the lake with us on Saturday? I think the explanation is that its a subject verb agreement error but I'm not sure why

2. The dogs are my favorite kind of pet.

3. How long the storm lasted?

4. Byron is seeing Diane for three months now.

5. Brian wrote so good on the test that he doesn’t have to take the next writing class.

Answer 1

A singular subject requires a singular verb, and a plural subject requires a plural verb. The subject in the sentence is "he," and "he" is a singular subject. Most singular verbs in English end in -s. Most plural verbs do not end in -s. This is just the opposite of what we normally associate with singular and plural.