【多选题】对于烯烃分子来说,分子产生顺反异构现象,必须在结构上具备两个条件,分别是以下哪两种?
C.
以双键相连的两个碳原子,必须和两个不同的原子或基团相连
D.
以双键相连的两个碳原子,必须和相同的原子或基团相连
【单选题】Which of the following statements is true?
A.
The volume of deals for hedging purposes is much higher than that for arbitraging and speculative purposes.
B.
The foreign exchange business for commerce and tourism must be done before 11a.m.on 2 January.
C.
It is hedgers' money that drives much larger volume of other transactions.
【单选题】“Where____myumbrella? ”“Somebody ____ it away by mistake、”
【判断题】信用证项下交单时,受益人需向银行提交原信用证、信用证修改书的正本和全套单据。
【简答题】阅读理解 It is a truth universally acknowledged that a single man in possession of a good fortune must be in want of a wife. However little known the feelings or views of such a man may be on his first en...
【单选题】色彩构成是指将( )的色彩要素按照一定的规则进行搭配组合,从而形成新的色彩。以上的空格中填入的内容应为。
【简答题】产生顺反异构的条件是_________、_________。