日光信号镜的一角有一个观测孔,围绕观测孔刻有()。①十字线;②同心圆环
A.①
B.②
C.①②
参考答案:C
以下何者不符合缩窄性心包炎的病理生理改变()
A.左右心房和心室的舒张压增高且很接近
B.心脏指数和每搏指数降低
C.射血分数明显下降
D.动、静脉血氧含量差增大
E.心室舒张期顺应性下降
More and more students are ________ reading in our school.
A.benefiting from
B.comparing to
C.giving off
D.setting out