【单选题】古人洗衣服时,一般使用()浸泡的溶液,其中含有碳酸钾,能去污。
【简答题】实验室里,欲从草木灰中除去不溶性的固体杂质来提取固体碳酸钾. (1)此实验操作顺序为①称量样品;②溶解、沉淀;③______;④______. (2)用托盘天平称量样品时,若指针偏向右边,则表示______. A、左盘重、样品轻B、左盘轻、砝码重 C、右盘重,砝码轻D、右盘轻、样品重 (3)第③步操作,有时可能重复进行,这是由于______. (4)在进行第四步操作时,要用玻璃棒不断小心搅拌液体,...
【单选题】墨子有言:“志不强者智不达”,这句话的含义是( )
【简答题】三相异步电动机固有机械特性是在 、 、 条件下的特性。
【简答题】The forwarder can monitor the movement of goods on behalf of the consignee whe the consignee controls the freight.
【单选题】Whe and where to build the new factory ______ yet.
【单选题】Which is not a benefit of crowdsourcing?
A.
low-cost problem analysis
C.
unique ideas generated
D.
lack of customer loyalty
【单选题】The __________ question for him is to ________ whether bees could tell each other the exact position of a feeding place.