正位胸片上，动脉导管未闭的特征表现为（）
A.双房影
B.漏斗征
C.靴形心
D.梨形心
E.平腰征
参考答案：B
阅读对话，判断正(√)误(×)。
A: We have a new classroom.
B: OK. Let's go and have a look.
A: Look, five fans and four lights.
B: And a new computer. It's cool.
A: I like my new classroom!
B: Me too.
( ) 1. We have a new classroom.
( ) 2. We have two fans.
( ) 3. We have six lights.
( ) 4. We have a new computer.
( ) 5. We like the new classroom.
配制HCl标准溶液宜取符合标准的试剂规格是（）。
A、HCl（AR）
B、HCl（GR）
C、HCl（LR）
D、HCl（CP）
