As promised, here are a few more pesky words and how to use them.
Who and Whom
In most cases, “who/whom” refers to human beings. According to the American Heritage Book of English Usage, "Who is used for a grammatical subject, where a nominative pronoun [one that acts as the subject of a verb] such as I or he would be appropriate, and whom is used as the object of a verb or preposition."
Here is a helpful tip from The Blue Book of Grammar and Punctuation:
If you can replace a word with "he" or "she," then it is the subject of the sentence and you should use "who." If you can replace the word with "him" or "her," it is the object and you should use "whom."
Examples:
She goes to my doctor, who is the best in town. To whom did you speak? Tom is the person with whom I spoke. (Though frankly, I find it easier to just say “I spoke to Tom.”) :D
When it comes to That and Which:
“That” is used when referring to things. “Which” should never be used in reference to humans and is often used to introduce phrases that give additional information or asides.
Examples:
This book isn’t that interesting. The year that I was born, there was a big storm. (When it comes to “that,” you can often just delete it. “The year I was born, there was a big storm.”)
My book, which I published a year ago, is still a best-seller. (Ha! Thought I’d slip a nice daydream in there)
