Yes, it is a prepositional phrase.
Comma's are the hardest punctuation mark to place in a sentence. A comma can be placed after instead at the beginning of a sentence if the sentence is a continuation of the subject in the one before it.
Yes. Example: Unfortunately, I forgot to get milk while I was grocery shopping.
Yes, you can place a comma after "thus" if it is used at the beginning of a sentence to introduce a result or conclusion. For example, "Thus, we can conclude that the experiment was a success."
If "at" is the beginning of a phrase, then a comma would be used. So, an example: Turn left, at the green windmill, to go to the old man's house.
No, a comma is not necessary after "perhaps" when it is at the beginning of a sentence unless it is followed by a contrasting idea.
No, typically a comma is not needed after "otherwise" at the beginning of a sentence. It is not a coordinating conjunction that requires a comma to separate independent clauses.
no. "Sally and John went for a walk." there is a comma in front of "and" only when it is used as the beginning of another phrase. "Sally and John went for a walk, and then they went to the zoo." no.
When a sentence includes an extra phrase beginning with the word "that," a comma is typically not needed. The phrase acts as an essential part of the sentence's structure and does not require a comma to set it off.
I'm assuming you meant to ask: "If the word...", and not: "Is the word..." There is no comma after "oops." Start a sentence with a capital letter, and place an exclamation mark after the word "oops." Also, use a comma after the word "sentence", just before the "is there..."--or second-- part of your question. Oops! I've spent more time on this than I thought I would...
Sometimes
No, a comma should not be placed after "after" at the beginning of a sentence unless it is being used to set off introductory or transitional words.
The comma always goes after the name in the beginning of a letter.