I ran into this sentence today:
- there is a green car and a motorcycle on harriet street
Students are supposed to read it, and then correct it for errors.
The correct answer is: There are a green car and a motorcycle on Harriet Street.
In prescriptive grammar, this compound subject (two singular nouns linked by "and") requires a third-person plural to-be verb in order to maintain subject-verb agreement.
Most native English speakers would apply the "proximity principle", whereby the verb is conjugated according to the noun nearest the verb in the sentence.
Native speakers would say:
- There is a green car and a motorcycle...
- There are two green cars and a motorcycle...
- There is a green car and two motorcycles...
But of course the native speaker would be technically wrong using all but the second of the above sentences.
It is interesting how often prescriptive grammar rules are broken by conversational English. Problem sentences like the one above don't compute. Reading and/or teaching, "There are a green car and a motorcycle on Harriet Street." creates disonance in my head-computer. I think I will strike that sentence from today's lesson (or at least make it optional-only...)