应改成 We often hear her sing in the next room.
解析:hear sb. do sth. 表示“听到某人做了某事”,hear sb. doing sth. 表示“听到某人正在做某事" .而hear sb. to do sth. 应该是不存在的结构.
应改成 We often hear her sing in the next room.
解析:hear sb. do sth. 表示“听到某人做了某事”,hear sb. doing sth. 表示“听到某人正在做某事" .而hear sb. to do sth. 应该是不存在的结构.