某理想气体经历了一个内能不变的热力过程，则该过程中工质的焓变( )。
A．等于零 B．大于零 C．小于零 D．等于1
参考答案：A
标本的采集是分析前质量保证关键的一步，下列不正确的是（）
A.空腹采血
B.防止溶血，避免影响因素
C.标本处理及时，严防污染
D.选择合适的抗凝剂
E.边输液边采血
—May I come in? I’m sorry I’m late.
— Come in, please. But could you please tell me _______________?
A．why you are late again
B．what were you doing then
C．who you talked with
D．how do you come to school
