"In this year": Can anyone argue that the preposition in is unnecessary here, maybe even a hypercorrection? (Are there any situations where in is necessary?)
How many days are left in this year? How many days are left this year?
In this year, Tommy has grown 12 inches. This year, Tommy has grown 12 inches.
To stir up some debate, is in this year a prepositional phrase with year as the object? If so, how does this change with the phrase this year?
A construct such as "In this year's [some event], [this occurred]." makes sense because the phrase automatically becomes prepositional: in the [event] while year's becomes some kind of adjective. I'm not asking about this situation.
I suppose I'm interested in knowing whether in this year is grammatically correct. Can every sentence containing the phrase in this year be shortened to the one containing this year? (Do any grammar rules govern this?)