1. The professor explained the concept lengthily during the lecture.
教授在讲课中详细解释了这个概念。

2. The meeting went on lengthily, and many participants became impatient.
会议进行得很冗长，许多参与者变得不耐烦。

3. She answered my question lengthily, providing all the necessary details.
她详细地回答了我的问题，提供了所有必要的细节。