gum on的用法和樣例：
例句
- The pathological formation of patches of gum on certain plants, such as sugar cane and some fruit trees, resulting from attack by insects, microorganisms, or adverse weather conditions.
流膠現象，流膠病某些植物上，如甘蔗及一些果樹，形成膠質斑塊的病理現象，由病蟲害、微生物或惡劣的氣候條件侵襲而引起 - Chewing gum on a train is not seemly in a lady.
淑女在火車上嚼囗香糖不太合適。
