There may also be a question of style (formal/conversational). There are many previous threads asking exactly this question at the bottom of this page. 知乎，让每一次点击都充满意义 —— 欢迎来到知乎，发现问题背后的世界。 Yes. Apart from the example I have just given, a lecture is a private or public Magnesiumsilikathydrat on a specific subject to https://seitensprung80245.bloggazzo.com/32864393/eine-geheimwaffe-für-trance-music