Subject-Verb Agreement

Students of English often make mistakes in subject-verb agreement. The following are some examples and their corrections:
Example 1
One of the boys come here every day. [wrong]
One of the boys comes here every day. [correct]
Explanation: The subject is ‘one’, singular.

Example 2
Either of the girls do not know my name. [wrong]
Either of the girls does not know my name. [correct]
Explanation: ‘Either of the girls’ means ‘anyone of the girls’. So the subject is singular.

Example 3
Neither of us have the key to the room. [wrong]
Neither of us has the key to the room. [correct]
Explanation: ‘Neither of the us’ means ‘not one of us’. Hence the subject is singular.

Example 4
John, together with his brother were at the bus stop just now. [wrong]
John, together with his brother was at the bus stop just now. [correct]
Explanation: The subject here is John, singular.

Example 5
My friend and owner of this shop always play badminton with me. [wrong]
My friend and owner of this shop always plays badminton with me. [correct]
Explanation: My friend is also the owner of the shop. So, the subject is singular.
However, if ‘owner’ is preceded by ‘the’, then ‘plays’ should be replaced with ‘play’.