在核酸中，核苷酸之间的连接方式是A．2'，3'-磷酸二酯键 B．3'，5'-磷酸二酯

下列行为与孝敬父母的要求相违背的是[ ]

①考试不理想，借口个人隐私，不让家长知道

②把脏衣服留给妈妈洗，自己却躺在床上睡懒觉

③给劳累一天的妈妈洗脚

④利用星期天，帮助父母做家务

A．①④

B．①②

C．②③

D．③④

Many students agreed to come, but some students against because they said they don't have time.

A．were against because they said they did not

B．were against because they say they don't

C．were against it because they said they did not

D．were against coming because they said they don't

严重的吸气性呼吸困难最主要的特点是（）

A.呼吸深快

B.明显紫绀

C.三凹征

D.鼻翼扇动

E.哮喘音

放疗技师摆位时需要核对记录单上项目不正确的是（）

A.姓名

B.性别

C.职业

D.诊断

E.当日医嘱

列出猪和家禽常见的EAA名称，常见拮抗氨基酸对、转化氨基酸对。