4.Since coal contains fewer hydrogen atoms than oil,then have to add some extra hydrogen to the gas.1.此处since引导原因状语从句?2.请挑重要的简要地说下since的用法

4.Since coal contains fewer hydrogen atoms than oil,then have to add some extra hydrogen to the gas.1.此处since引导原因状语从句?2.请挑重要的简要地说下since的用法 captive coal coal charcoal Coal Steam RECTANGULAR COAL 英语翻译METHODSMine characteristicsThe coal mine in the Mbeya Region of Tanzania has 600 workers,of whom 240 are involved inunderground tasks.It has operated at a capacity of 150 000 tonnes of bituminous coal per year since 1988.The coal seam is since Regarding Drawings of Coal Nut-size coal coal-fired power coal是什么?它是什么? coal sizer是什么东西? dirty coal是什么意思 coal的意思 coal terminal 怎么翻译? 以contain造句 辨析include,contain contain one's excitement