开始添加蛋黄的月龄是
A．1个月～2个月B．2个月～3个月C．4个月～6个月D．6个月～9个月E．10个月～12个月
参考答案：C
With the country's population reaching 1.6 billion in the mid of this century, most of China's rivers,
including the Yellow River, ____.[ ]
A. is drying up
B. will be drying up
C. dry up
D. have dried up
关于膈肌的叙述，哪项是不正确的()
A．肺气肿时，膈肌下降
B．急性无气肺，膈成为高位
C．通常是左膈比右膈高
D．肺、纵隔肿瘤时，可出现膈肌麻痹
E．大量胸水时，膈影像定位困难
untry's population reaching 1.6 billion in the mid of this century, most of China's rivers,