单词：pentachloroethane
单词：pentachloroethane 相关文章
Lesson 92 A Box Of Matches 第92课 一盒火柴 We need fire every day, to warm our houses, or to cook our food, or to give us light. 我们每天都需要利用火来给房间加温、烹饪、照明。 Even savage tribes use fire for such purposes
英国学生科学读本
Up in the Sierra Madre Mountains, in a bowl-shaped valley, is the capital of Mexico. 在马德雷山脉上有一个碗形的山谷，里面坐落着墨西哥的首都， It is called Mexico City, so you dont have to learn a new name. 叫做墨西哥城
美国学生世界地理教材
Lesson 57 Sulphur 第57课 硫 Did you ever have to take a mixture of brimstone and treacle? This mixture has not a pleasant taste, but it is a useful medicine; and if it will do us good, we should not care much whether it has a nice taste or not. 小朋
英国学生科学读本
The fumes of burning sulphur will bleach straw, silk, and other things, and make them white and clean. These fumes are also useful for killing the germs which cause fevers and other diseases. 燃烧的硫磺冒出的烟，可以漂白稻草、丝绸和
英国学生科学读本
Oh, my God, are you choking? Oh, my God, I feel like you're choking! Is anyone here a doctor? What am I saying? I forgot where I am. Has anyone here ever seen What do you do when a girl is choking? I just back up a few inches. What do we do? What do
跟着美剧练发音
The State Council, China's cabinet, has released its timetable to upgrade fuel quality nationwide before 2017. The new standard for petrol and diesel, with sulphur content within 10 parts per million, is expected to be in practice nationwide by 2017.
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