I assume not because when I typed this sentence into MS Word, "The opportunity to study in foreign countries where religious history originated would be an uniquely unforgettable experience," it underlined the "an" before uniquely and corrected it to "a." Perhaps it is an exception, and besides, it does sound better to say "a" instead of "an" before the word "unique."
A word to put in front of 'on' to make a new word is up (upon).
The word "next" can be put in front of "step" to form the phrase "next step."
The prefix that can be put in front of "care" is "dis-" to form the word "discare."
Watercress.
Sometimes, while writing, I put commas in front of the word 'while'.
When you put a word in front of a quote, it is called an attribution. This is used to indicate who is speaking or to provide context for the quote.
Trustworthy
PORridge
The prefix "un-" can be put in front of the word "describe" to create the word "undescribe."
cellmateplaymateteammateworkmatestalemateshipmateroommateseatmatecheckmateclassmateschoolmatemessmatestablemate
windowpane
foot