1. 大多數研究者認為吸煙是患上肺癌和咽喉癌的重要原因。
2. 需要強調指出的是,電源僅僅是一種能讓電流在電路中循環流動的裝置。
3. 如果每一百萬份水中礦物質或鹽的含量少于500份,該水質則被視為高品質并適于飲用。
4. Covering 71 percent of the earth surface, ocean is a basic component of life support system on the earth, as well as a treasury of resource and an important adjuster of environment.