皮肤科中常用化妆品有哪几类，他们的作用和用途是什么？
参考答案：
皮肤科中常用化妆品有皮肤清洁剂、保湿霜和防晒霜。
（1）皮肤清洁剂：能在清洁皮肤的同时，一定程度上维持皮肤微环境的平衡。多种洗面奶常用于痤疮、酒渣鼻以及皮脂溢出症的辅助性治疗。
（2）保湿霜：能有效维护皮肤的生理功能，对皮肤角质层及屏障功能具有修复和维护的作用，是干性皮肤、敏感性皮肤及多数湿疹样皮肤疾病重要的辅助性治疗产品。
（3）防晒霜：能明显减低紫外线对皮肤的作用，减少紫外线对皮肤的损伤、减轻皮肤色素性疾病的发生和发展，对预防光老化的发生也有一定作用。
Read the following text and choose the most suitable heading from A-F for each paragraph. There is one extra heading which you do not need. F=A+E
81. _______________ Airplanes are used to carry passengers, cargo and mail. Air transport companies operate scheduled airlines and non-scheduled services over local, regional, national, and international routes. The aircraft operated by these companies range from small single-engine planes to large multiengine jet transports. 82._____________ The first air passenger services began in 1910, when dirigibles began operation between several German cities. The first scheduled airplane service to carry passengers began in the U.S in 1914. Several experimental airmail flights took place in India, Europe, and the United States before World War I, but air transport service did not become a true business until after the war. 83. _____________ During World War Two, intercontinental air transport became firmly established. After the war the new long-distance transports with advanced facilities were increasingly able to avoid storms and strong wind and make flights more economical and consistent. A new generation of "jumbo-jet" transports began operations in 1970, and the supersonic transport entered passenger service in 1976. 84. _________ During the 1970s the number of domestic passengers on U.S airlines increased about 78%, and during the 1980s the figure was up about 58%. In 1990 there were 41.8 m  illion international passengers, the figure was a 75% increase over 1980. The total cargo flown by U.S airlines almost doubled during the 1980s, from 5.7 billion to 10.6 billion ton-miles in 1990.85. ________________ Major airports provide a wide range of facilities for the convenience of millions of travelers. These range from such basic services as  ticket-sales counters and resultants to luxury hotels, shopping centers and play areas for children. International airports must also have customs areas and currency-exchange counters and so on. |