✨ Best Answer ✨
①
(1) 〇
(2) 〇
(3) is living(現在進行形) → has been living(現在完了進行形)
(4) 〇
②
(1) 〇
(2) 〇
(3) Ben (had) already (left) for London when I arrived at the airport. ※leave for … …に向けて出発する
(4) (was) (making):過去進行形 ※make a phone call 電話をかける
③
(1) 〇
(2) By next year, economic problems are going to be even more serious.
(3) I [will be playing](未来進行形) a tennis match at this time tomorrow.
(4) 〇
参考にしてください。