永存动脉干的二维超声检查有什么特殊所见A．两个大动脉显示平行

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问题单项选择题

永存动脉干的二维超声检查有什么特殊所见

A．两个大动脉显示平行并列

B．肺动脉显示明显大于主动脉

C．从各个切面图均不能显示独立存在的主肺动脉或其分支，只能从动脉干处显示其存在

D．肺动脉与左心室连接

E．肺动脉从冠状动脉起源

答案

参考答案：C

阅读理解

For a 400-year-old art form, opera had a bad fame: overweight actresses singing the words which were hard to understand in one of those romantic languages you were supposed to learn in high school. And with tickets costing as much as $145 a performance, operagoers also had a certain appearance in people’s mind: rich, well-dressed and old.

But now opera companies around the country are loosening their ties and kicking off their shoes in an attempt to keep opera alive and take it to a younger and not so wealthy audience.

Opera producers have found that to attract this crowd, they need to associate opera with the common people. That means no formal suits, old-styled theatre or bank-breaking ticket prices. And because young people don’t or won’t come to the opera, companies are bringing the opera to them, giving performances in such usual places as parks, libraries and public schools.

The Houston Grand Opera’s choice is the public library, where it performs “mobile operas”, shortened versions of child-friendly operas. This summer’s production is Hansel & Gretel. By performing smaller versions of large productions, producers are able to make people interested while keeping costs at a reasonable level. The San Francisco Opera, which will be celebrating its 75th anniversary this year, is staging Cinderella free of charge, keeping costs down by employing students from its Young Artists’ Training Program.