缩窄性心包炎最常见的体征是
A．气促
B．肺部罗音
C．心浊音界增大
D．颈静脉怒张、肝大、腹水
E．奇脉
参考答案：D
You should apologize ____ your teacher ______ being late again.
A．to; for
B．for; to
C．/; for
D．to; to
简述覆盖除草的原理及其除草方式？
