出现跨瓣压差时二尖瓣狭窄面积在
A.1.5~2.0cm4
B.≤2.0cm2
C.≤1.5cm2
D.≤1.0cm2
E.2.0~2.5cm2
参考答案:B
—Don’t forget their address and telephone number.
—I will _____ in my notebook.
A.write them down
B.write it down
C.write down it
D.write down them
对老年父母有稳定收入来源的,子女可以不承担赡养义务。