极性最大的化合物是
A.大黄素B.大黄素甲醚C.大黄酸D.芦荟大黄素E.大黄素葡萄糖苷
参考答案:E
传染性非典型肺炎的传播途径是()
A.密切接触传播
B.接触患者呼吸道分泌物
C.短距离飞沫传播
D.血液传播
E.虫媒传播
The Cognitive Approach seeks in () a basis for second language teaching.
A.American structural linguistics and behavioural psychology
B.tructural linguistics and cognitive psychology
C.functional linguistics and habit-formation theory
D.transformational grammar and cognitive psychology