It is a general rule in English that singular verb goes with singular noun.
However, I find it strange when in certain clauses like "there were no problems", the verb is plural. In this case, does "no problems" have the same meaning as "no problem"? If it does, why is the verb plural?
In addition, if my sentence subject is 2 non-count nouns, or a non-count noun and a singular noun, joined by a conjunction like "and", will the verb be singular or plural and why?
Finally, when we combine 2 nouns together without any word in between, like "sport products", do we always have to use the singular form for the 1st noun? What is the difference in meaning between "sports products" and "sport products"?
For the case when we use a preposition to connect nouns like "the price of laptop", is OK if we use "the prices of laptop" or do we have to use "laptop prices"?
Edit:no problems means zero problem or it means that there is either zero or one problem? Either way, the meaning suggests it is no more than one, and hence should be singular. In other words, I think it is more reasonable for no problems to go with a singular verb.
**P.S: Don't get me wrong. I am not criticizing anything. I like English but sometimes I do find strange things, from my point of view, non-native speaker view. That's why I ask this question.
***P.S 2: for the last question, I'll make a separate topic for further discussion.