将喉弹性膜分为上下两部分的是（）。
A.甲状软骨上缘
B.甲状软骨下缘
C.室带
D.喉室
E.声带
参考答案：D
All that he had learned only made him feel how little he knew in comparison with ______ remained to be known.
A．what was
B．what
C．which was
D．that
试述小学班主任在工作中所扮演的几个主要角色
