I am having a massive debate about whether the following sentence is grammatical:
The tag was created and is printed.
The issue is the switch of tense between was created and is printed. Some argue that this is invalid English because of the inconsistency of the tenses. However, it seems to me that the presence of the conjunction and allows for this because the tag applies to both verb phrases and makes the above sentence a short hand form of something like:
The tag was created. It is printed.
It's possible that this is only the case with forms of to be, however, or perhaps just the passive. For example, the following certainly does not seem grammatical:
He threw the rock and catches the ball.
But there is a fundamental difference between the two examples, besides the forms of to be. In the latter, the subject of the sentence is not also the object of the verb as it is in the sentence under question. As such, such a shift in mentality with just a conjunction is not warranted.
It gets very confusing. Is it grammatical to switch tenses in a predicate at all? If so, under what circumstances?