单词：optical cement
单词：optical cement 相关文章
Grammar Girl here. Todays topic is cement versus concrete. Guest writer Sal Glynn writes: Accuracy is important. You might think concrete and cement are interchangeable, but you'll quickly find that you're mistaken when some guy at Home Depot rolls h
英语语法 Grammar Girl
Cement is a major component of concrete, the world's most widely used man-made material, an integral part of roads, bridges and buildings. But making cement requires heating limestone and other materials to very high temperatures, a process that rele
VOA标准英语2010年(一月)
China's Tibet Autonomous Region is about to achieve a universal coverage of fibre-optical broadband service ahead of its schedule. As China further rolled out its universal broadband project, Tibet's broadband service is looking to reach 98% of admin
2018CRI中国国际广播电台