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Alex is texting his coworker to apologize for a delayed reply. Choose ALL the messages that are grammatically correct and natural for this situation.
The correct answers are Sorry for taking so long to get back to you! and Sorry it took me a while to reply.
After the preposition for, we must use the gerund form (taking).
The phrase "it took me a while" is followed by a to-infinitive (to reply), not "for" + gerund.