56. He hasn't chatted with his classmates through the internet for ages.
⇒ It's age since he last chatted with his classmates through the internet.
31. They started building the bridge two years ago.
⇒ They have built the bridge for two years
32. Mai commenced writing the lesson twenty minutes ago.
⇒ Mai has writed the lessons twenty minutes ago
33. My Vi began counting her lucky money five minutes ago.
⇒ My Vi has counted her lucky money five minutes ago
34. You started flirting with me forty minutes ago.
⇒ You have flirted with me forty minutes ago
35. She began listening to the music fifteen minutes ago.
⇒ She has listened to the music since fifteen minutes