Is the following sentence linguistically acceptable?
It was John's that I stole bike.

unacceptable

Is the following sentence linguistically acceptable?
You shouldn't play with rifles because to is dangerous.

unacceptable

Is the following sentence linguistically acceptable?
John is in the room.

acceptable

Is the following sentence linguistically acceptable?
Abernathy admitted that the poison pen letter had been written by my sister and himself.
acceptable