【判断题】The central theme of a paragraph is usually summarized in what is called the topic sentence. It often appears at the end of the paragraph; however,it may also be found in the middle or at the beginnin...
【多选题】硫化氢的主要来源有()。
B.
天然气或原油中的有机物在化学反应或微生物作用下能分解产生硫化氢
D.
含硫的矿石(如硫化亚铁FeS)与酸接触产生H 2 S
【单选题】为了给青少年学生创造艰苦的环境让他们经受锻炼,国防教育中的()给青少年们提供了极佳的平台。
【简答题】资产阶级维新派自身弱点和局限的主要变现是什么?
【判断题】The theme of a send-off or farewell party or dinner is usually related to past events instead of showing resolutions or hopes for the future.