Object of a PrepositionThe words that follow a preposition are called the object of the preposition.
As covered in the lesson on prepositions, a preposition usually sits before a noun (i.e., a word like dog, man, house, Alan) or a pronoun (i.e., a word like him, her, which, it, them). This is worth knowing, because the object of a preposition is always in the objective case, and pronouns change in this case. (That sounds really complicated, but it just means that he changes to him when you say something like next to him, and she changes to her when you say something like It's for her. In general, native English speakers have little trouble forming the objective case.)
Who and WhomThe problem seems to be with who and whom. These two words are no different from pairings like I/me, he/him, she/her, we/us, and they/them, but they are responsible for a lot more grammar mistakes.
The word whom is the objective case of who, and this pairing causes some confusion. (This is covered more in the lesson Who and Whom.)
should be "Two hits to whom?"
(grammatically dodgy joke in a university magazine)
WHOM AFTER A PREPOSITION
Many are unsure when to use who and whom. One thing is for certain: Always use whom after a preposition.
should be "by whom?"
WHETHER AFTER A PREPOSITION
Some writers are unsure when to use whether and when to use if. After a preposition, only whether can be used:
See the lesson Whether and If.
YOU AND I / MY WIFE AND I
Too often, people use I in expressions like you and I or my wife and I when they should be using me.
Remember, prepositions govern the objective case. Therefore, the word I must change to me when it is the object of a preposition (i.e., follows the preposition). The fact that it is preceded by you and or my wife and is actually irrelevant.
You should only use I in an expression like you and I when it is the subject of the verb. For example:
If the terms objective case and subject of a verb are confusing, there is a neat trick to determine whether to use the you and I form or the you and me form. Simply remove everything apart from the I and try your sentence again. You will naturally use the correct version.
Question: I or me?
Step 1: Remove my wife and
Step 2: Try the sentence again.
Step 3a: It was proposed by I.
Step 3b: It was proposed by me.