紫绀的原因是 A．血液还原血红蛋白增多 B．血红细胞大量被破坏 C．局部瘀血 D．毛

句型转换。

1. He is much taller than his brother.(改为同义句)

He is taller_____ _____than his brother.

2. They often come here now.(改为否定句)

They_____come here_____.

3. She felt so tired that she couldn't walk forwards.(改为同义句)

She felt_____ _____ _____walk forwards.

4. Whatever he did,he tried his best to do it．(改为同义句)

_____ _____ _____he did, he tried his best to do it．

5. He looked quite hopeless.(改为同义句)

He_____ _____ _____quite hopeless.

恶性骨肿瘤最主要的确诊依据是()

A．家族史

B．临床表现有明显的体征

C．病理组织学检查

D．化验检查

E．影像学检查

排水系统根据所接纳的污废水类型不同，可分为（）。

A．生活污水管道系统

B．生产污水管道系统

C．工业废水管道系统

D．屋面雨水管道系统

支气管哮喘与心源性哮喘一时难以鉴别时，应采用下列哪种药物治疗

A．异丙基肾上腺素
B．肾上腺素
C．西地兰
D．氮茶碱
E．吗啡

与肺通气非弹性阻力有关的是（）

A．肺泡表面张力

B．肺组织本身的弹性回缩力

C．两者均有

D．两者均无