【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、”
【简答题】A、B、C是三种常见短周期元素的单质.常温下D为无色液体,E是一种常见的温室气体.其转化关系如图(反应条件和部分产物略去).试回答: (1)E的结构式是______,F的电子式是______ (2)写出F与D反应的离子方程式并标出电子转移的方向和数目______ (3)物质Z与B互为同素异形体,它常用于对空气进行杀菌、净化和水果保鲜等.Z和酸性碘化钾溶液反应生成B和碘单质,反应的离子方程式是___...
【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...
【多选题】What need be taken into consideration to determine whether a meeting is necessary?
A.
Must the job get done via presenting, discussing and decision making, etc.?
B.
What time is it possible to set out to work?
C.
Is there an alternative way to deal with the mission?
D.
What objective and outcome need to be reached?
【简答题】产生顺反异构的条件是_________、_________。
【单选题】Which of the following adverbs in italic is NOT used to modify adjective?
A.
This cake is much better than that one.
B.
The soup is a bit too salty for me.
C.
Mary is old enough to get married.
D.
The bus is too crowded to get on.