1.

Two or more singular subjects joined by and take a plural verb.


Radha and Meera are coming.


2. Two or more singular subjects joined by and used for the same person take a singular verb.


The producer and designer of the project has came.



3. If the singular subjects are preceded by each or every use singular 

Each of us was afraid of being download.


IF two or more singular subjects are joined by or, nor either, neither nor, the verb is singular.

Either Rita or Geeta is lying.


Either the child or the parents have to come.


4.


Collective noun taken singular verb when talked of as a whole and a plural when we talk of the individual parts of it.

The committee has chosen its president. 


5. Some nouns which are plural in form but singular in meaning take a singular verb. 

Mathematics is my favourite subject.

Statistics show that India's covid 19 cases are plummeting.

6. words joined to a singular subject by with, in addition, as well as are supplementary and do not affect. 

The principal, along with all the teachers have/has come.


7.

Subject is a relative pronoun, verb should agree in number and person with the antecedent

I, who is your friend, am honest to you.

8.

Two subjects is a sentence end not in the same number the separate auxillary verb. 


Two men were dead and one was alive.


 9. Two auxillary verbs one used with one main verb. the form of the main verb.

I have eaten and will eat pizza everyday.

( I may be incorrect for this rule, please correct me If I am wrong).


10. Universal truth 

Our teacher said that the Earth moves around the sun. 

11. The past tense in the main clause must follow other by past 

He saw that the clock had stopped.