【简答题】"Why would you leave behind your comfortable bed, your home, your family and friends? Why do you want to go alone?" When you are living out of a backpack for a period of time, you may often get questi...
【单选题】Once you________drugs, it's hard to manage to get rid of them. [ ]
【单选题】砷及其化合物在工业上的应用颇广,并具有很强的毒性,除草剂、杀虫剂、防腐剂、涂料及许多合金中都有它们的身影,这导致水中砷污染日益严重。研究人员最近发现,烟灰可以制成净水材料,用来净化水中的砷。实验显示,这种材料能成功地把一杯含砷量为233微克/升的水降到8微克/升(净化量超过了96%),达到世界卫生组织的要求。因此,这种净水材料可以用作过滤器,在全国进行推广。 以下哪项如果为真,最能加强上述观点?
A.
批量生产净水材料需要大量烟灰,但现今还未找到获得的途径
C.
烟叶中含有多种重金属及其他有害物质,会残留于灰烬中
D.
该净水材料只对水中的砷有过滤作用,但对其他有害物质则起不到净化作用
【简答题】Workplace success! How can you get the job you want? And once you’ve got it — how can you keep it? Our three-week online course takes you through the whole process: from finding your ideal job to maki...
【单选题】Once you ______ the habit of smoking, it is hard to quit.