Your bot can reply to mentions on Twitter. When another user tweets with @bots-user in the tweet the bot will reply to the mention if you have reply to mentions enabled.
The bot can also reply to direct messages.
It is also possible to config the bot to search and reply to tweets, but you need to be very careful doing this so as not to spam.
You can import tweets into the bot for it to learn from on the bot's Twitter page in its Admin Console.