Finish the dramatic teenager's text message to her best friend. Choose the correct word to complete the sentence.

Can you believe he read my message exactly five minutes _____ and still hasn't replied?!

The correct answer is ago.

We use ago with a period of time to express how far back in the past an event happened (e.g., "five minutes ago", "two days ago"). It is almost always used with the simple past tense (in this case, "he read").