若实数m,n满足,且m,n恰好是等腰△ABC的两条边的边长,则△ABC的周长是( )A. 12 B. 8 C. 10 D. 10或8 答案:【答案】C【解析】根据非负数的性质求出的值,根据等腰三角形的性质求解即可. 当三角形的腰长为2时,,构不成三角形;当三角形的腰长为4时,三角形的周长为:.故答案选:C.Background music may seem harmless, but it can have a
powerful effect on those who hear it. Recorded background music first found its
way into factories, shops and restaurants in the USA. Very soon it spread to
other parts of the world. Now it is becoming difficult to go shopping or eat a
meal without listening to background music.
To begin
with, background music was intended simply to create a soothing (舒适的) atmosphere. Recently, however, it's becoming a big
business. An American marketing expert has shown that music can boost(提升) sales or increase factory production by as much as a
third.
But it has
to be the light music. Lively music has no effect at all on sales. Slow music
can increase receipts(收入) by 34%. This is probably because shoppers
slow down and have more opportunity to spot items they would like to buy. Yet,
slow music isn't always the answer. The expert found that in restaurants slow
music meant customers took longer to eat their meals, which reduced overall
sales. So restaurant owners might be well advised to play faster music to keep
the customers moving-unless, of course, the resulting indigestion(消化不良) leads to complaints.
1.Background music was first used ________.
A.in the
cinemas and theatres in the USA
B.in the
offices and hospitals in the USA
C.in the
schools and churches in the USA
D.in the
factories, shops and restaurants in the USA
2.An American marketing expert has found background
music can __________.
A.increase
sales or factory production
B.create a
soothing atmosphere
C.make people
slow down
D.make people
forget their worries
3.Slow music is useless in ________ in increasing
sales.
A.shops
B.restaurants
C.factories
D.cinemas
4.Restaurant owners are advised to play ________ to
increase overall sales.
A.lively music
B.loud music
C.slower music
D.faster music