真空中波长为λ的单色光，在折射率为n的透明介质中从A沿某路径传播到B，若A、B两点周

哪个查询是包含另一个选择或操作查询中的SQL SELECT语句，可以在查询设计网格的“字段”行输入这些语句来定义新字段，或在“准则”行来定义字段的准则（ ）。

A．联合查询

B．传递查询

C．数据定义查询

D．子查询

膝关节脱位行血管造影的指征是（）

A.双下肢动脉搏动不对称

B.常规检查

C.患肢未触及动脉搏动

D.超声检查可替代，无需行血管造影

E.MRE可替代，无需行血管造影

Vienna was one of the music centers of Europe during the classical period, and Haydn, Mozart, and Beethoven were all active there. As the (1) of the Holy Roman Empire (which included parts of present-day Austria, Germany, Italy, Hungary, Czech and Slovakia), it was a (2) cultural and commercial center (3) a cosmopolitan character. Its population of almost 250,000 (in 1800) made Vienna the fourth largest city in Europe. All three (4) masters were born elsewhere, but they were (5) to Vienna to study and to seek (6) . In Vienna, Haydn and Mozart became close friends and influenced each other’s musical (7) . Beethoven traveled to Vienna at sixteen to play for Mozart; at twenty-two, he returned to study with Haydn.

Aristocrats from all over the Empire spent the winter in Vienna, sometimes bringing their private (8) . Music was an important part of court life, and a good orchestra was a (9) of prestige. Many of the nobility were excellent musicians.

Much music was heard in (10) concerts where aristocrats and wealthy commoners played (11) professional musicians. Mozart and Beethoven often earned money by performing in these intimate concerts. The nobility (12) hired servants who could (13) as musicians. An advertisement in the Vienna Gazette of 1789 (14) : " Wanted, for a house of the gentry, a manservant who knows how to play the violin well. "

In Vienna there was also (15) music, light and popular in (16) . Small street bands of wind and string players played at garden parties or under the windows of people (17) to throw (18) money. Haydn and Mozart wrote many outdoor entertainment (19) , (20) they called divertimentos or serenades. Vienna’s great love of music and its enthusiastic demand for new works made it the chosen city of Haydn, Mozart and Beethoven.

18（）

A.off

B.away

C.about

D.down

软件特性中，在给定的时间间隔内，程序成功运行的概率指的是（）。

A.有效性

B.可适应性

C.正确性

D.可靠性

临床上使用的为α型和β型的混合物（）

A.蒿甲醚

B.甲硝唑

C.枸橼酸乙胺嗪

D.盐酸左旋咪唑

E.吡喹酮