【单选题】下列基团按次序规则从小到大(优)排序正确的是:
A.
-Cl , -C(CH3)3, -OCH3, -CH3
B.
-Cl , -OCH3, -C(CH3)3, -CH3
C.
-OCH3, -C(CH3)3, -CH3, -Cl,
D.
-CH3, -C(CH3)3, -OCH3, -Cl
【简答题】'The world's oceans are slowly getting more acidic,”say scientists. The researchers from California report that the change is taking place in response to higher levels of carbon dioxide in the atmosph...
【单选题】Which of the following statements is INCORRECT?
A.
Changes are slowly taking place in all sectors of the British society.
B.
The gap between working-class and middle-class young people is narrowing.
C.
Differences in income will remain but those in occupation will disappear.
D.
Middle-class people may sometimes feel inferior to working-class people.
【单选题】下列基团中质子按化学位移值的从大到小的顺序排列正确的是( )
A.
CH 3 F >CH 3 O> CH 4 > CH 3 N
B.
CH 4 > CH 3 N > CH 3 O> CH 3 F
C.
CH 3 F >CH 3 O> CH 3 N> CH 4
D.
CH 3 N> CH 4 > CH 3 O > CH 3 F
【单选题】袁隆平曾结合自己的科研经历,语重心长地对年轻人说: “ 书本知识非常重要,电脑技术也很重要,但是书本电脑里种不出水稻来,只有在田里才能种出水稻来。 ” 这表明 ( )
【判断题】留园被认为是苏州古典园林中以少胜多的典范。
【单选题】按照基团次序规则,下列基团优先次序从大到小排列,正确的是:a. —CH3 b. —OH c. —NH2 d. —Cl