理想液体的伯努利方程中没有（）。
A.动能
B.势能
C.热能
D.压力能
参考答案：C
慢性湿疹最需与下列哪种疾病鉴别
A．急性湿疹
B．慢性单纯性苔藓
C．荨麻疹
D．特应性皮炎
E．药疹
It was difficult to tell exactly _______ the saying began, but it is possible that it was in the theatre or movie industry.
A．where
B．when
C．why
D．that
