4.They used to be,but the city has improved a lot since I came here a few years ago.译：
问题描述：
4.They used to be,but the city has improved a lot since I came here a few years ago.译：
答
They used to be,but the city has improved a lot since I came here a few years ago
他们曾经是,但这个城市已经有了很大改善因为我几年前来到这里