adj & verbs with prepositions - pronunciation

In speech, prepositions are usually unstressed. They would be unstressed, for example, in "I'd like to apply for a loan", or "I'm so proud of you".

They can be stressed when a contrast is being made, or there is some other reason for emphasis: "I told you to put the food in the freezer" (not, say, on top of it); "Finished my bath? I'm not even in it yet!"; "Stop talking over me!".

Here's a gift for you. <-- FOR is not stressed, and so it'll be replaced by a weak form, which will sound like FUR.
What are you waiting for? <-- Exception: this FOR is nor stressed completely, but you could say it has a secondary stress, and so it's not reduced. This happens when you have prepositions or words that might take the weak form at the end of a statement. Another example like this: Give it to me ("to" is weak) - I don't want to ("to" is not weak).