呼吸系统监护测定选用（）
A.血尿素氮
B.3P试验
C.黄疸指数
D.血气分析
E.Swan-Ganz气囊漂浮导管
参考答案：D
织物勾丝性测试中如果中勾丝占全部勾丝比例的3/4以上则顺降级别为（）.
A.1/4
B.1/2
C.1/3
D.1
It's a beautiful, sunny day! There _____ many people here on vacation.[ ]
A. be
B. am
C. is
D. are
