I often hear her sing. (经常) I saw her come into the classroom. (已发生)
I saw them playing basketball yesterday. ( 某次或正在发生)
全世界: around the world = in the world = all over the world.
All these shows have one thing in common. 所有的这些节目都有一个共同之处。
常见的; 普通的 如: common knowledge 常识; common people 老百姓
共同的; 公共的 如: common habits.
have sth. in common (with sb.): (与某人) 在某方面有共同之处。
In common with sb./sth : 与...一样: