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举一反三
【单选题】化合物 C 3 H 5 Cl 3 , 1HNMR 谱图上有 3 组峰的结构式是 ( )
A.
CH 3 -CH 2 -CCl 3
B.
CH 2 Cl-CH 2 -CHCl 2
C.
CH 2 Cl-CH 2 -CH 2 Cl
D.
CH 3 -CCl 2 -CH 2 Cl
【单选题】Scholars and students have always been great travelers. The official case for "academic mobility" is now often stated in impressive terms as a fundamental necessity for economic and social progress in...
A.
salaries and conditions are better abroad
B.
standards are higher at foreign universities
C.
they are eager for new knowledge
D.
their governments encourage them to travel