Despite being classified as a depressant, alcohol initially acts as a stimulant on the central nervous system.虽说被划定为镇静剂，酒精最初却是被当作中枢神经系统的兴奋剂。Psychoactive substances are commonly grouped toare stimulants, depressant, or ha...
A crawler, device of girth welds testing outside pipeline is developed successfully.成功地研制了管道外检测机械装置—爬行器.The pool is divided into three sections with a crawler lane for beginners.泳池分三部分，有为初学者而设的慢泳道。The Google crawler does...
If such materials became generally available to the optics industry the payoffs from such a breakthrough would be enormous.如果这些材料能够普遍用于光学产业，那么这一突破带来的收益将非常巨大。This part of the subject is called physical optics.这部分内容叫做物理光学....