慢性阻塞性肺病最确切的诊断指
A.支气管哮
B.慢性支气管炎
C.肺气肿
D.慢性阻塞性支气管炎合并阻塞性肺气肿
参考答案:D
She looked up and nodded for me ______..
A.to come in
B.coming in
C.came in
D.come in
镁原子和镁离子都属于镁元素,是因为它们有相同的( )
A.电子数
B.质子数
C.中子数
D.最外层电子数