Traditional grammarians tell us that we never ___ end a sentence with a preposition. However, it is not clear why they ___ declared] this rule.
There are many situations in which one ___ end a sentence with a preposition. For example, when you ___ using a verb expression, such as look up, you wouldn't say, "Up which keyword did you look?"
Split infinitives ___ profited as well. How would "To go boldly where no man ___ gone before," sound to a Star Trek fan?
And starting a sentence with but ___ not permitted. Hopefully, you ___ never done that. Unfortunately, that is another rule that I ___ not going to ever understand. Why ___ grammarians make up such nonsense?