图中所示的是()
A:leg
B:face
图为氨基酸分子的结构通式,下列叙述正确的是( )
— You think studying English well is difficult, but we know interest can be any way.
一 Thank you for your advice.
化合物X是抗心律失常药物泰达隆的医药中间体,其结构简式如图所示。下列有关化合物X的说法正确的是( )