在纷繁复杂的视觉符号系统中，（）是视觉传达设计的基本构成要素 A.文字 B.标志

设p：实数m满足m²-4am+3a²＜0（其中a＜0）；q：实数m满足方程（m+4）x²-（m+2）y²=（m+4）（m+2）为双曲线．若^¬p是^¬q的必要不充分条件，求实数a的取值范围．

直线l上有A、B、C三点，直线l外有点P，若PA=5cm，PB=3cm，PC=2cm，那么点P到直线l的距离是（    ）

A.等于2cm      B.等于3cm     C.小于或等于2cm      D.无法确定

Modern Manners

Philip Howard answers your questions on contemporary etiquette (礼仪)

Philip Howard,

When my friend and I (two ladies of a certain age) go out to have a meal, she always leaves an extremely large tip. At times, the tip will equal the amount of one of the main dishes—sometimes it comes to about 30 per cent of the bill. I feel 15—20 per cent is adequate for services offered and depending on the type of restaurant. At a cafe I would like to leave 15 per cent or a bit more depending on the service and etc. A larger tip would be appropriate if we are in a big city or a nicer place. My friend says “Well, I am sure they are not driving a Mercedes (奔驰汽车).” Well, neither am I, and how does she know? Who is correct and how can I make changes? I might add I do truly feel tipping should be based on good service, and also if you frequent a place and know the staff a larger tip is OK. I would never hesitate to tip a waitperson. I always leave to the higher side.  

     Yours,

                                      Barbara Bade

Barbara Bade,

Americans are more generous tippers than the British. I suspect that 10 per cent for a tip is about normal in the UK. Tipping is a strange survival in our age of supposed equality and minimum wages. Your friend has a generous nature and deep purse. I do not see why you cannot let her tip whatever she wants, and do your own thing. I agree that a tip should be a reward for good service and general good feeling. If the service is rotten and the meal a disaster, we should withhold a tip and explain why we are doing so. Few of us have the chutzpah (厚颜) to do this. Sensible restaurants have a box for tips, so that they are shared out among the staff, including those in the kitchens whom we do not see. (I trust that the management does not receive the money as extra profit.) I look forward to the day when waiters and other servants are paid a good enough living wage, so that they do not have to depend on the generosity of strangers to survive. To wait at table is just as honorable a way to earn a living in this wicked world. If you are pleased with the meal and cheerful service, you should tip as handsomely as your purse affords. I don’t suppose that your waiter / waitress is driving a Mercedes, even in the States. 

Yours,

Philip Howard

60. We can learn from the first letter that Barbara prefers ___________.

A. changing her own ideas on how to tip waiters

B. leaving a bigger tip to the familiar waitpersons

C. eating at a café rather than in a nice restaurant

D. saving as much money as possible for herself

61. It can be inferred that Barbara’s friend tips waiters heavily ________.

A. to show that she is well off                           B. because they are thought to be poorly paid

C. to show that she is generous                       D. because they have offered her full service

62. Besides quality of service, Philip regards __________ as principles of tipping.

A. taste of food and amount of one’s money

B. taste of food and the number of servants

C. generosity of strangers and the number of servants

D. amount of one’s money and generosity of strangers

社会调查方法可分为（）、（）、（）和个案调查。

阿司匹林片的正常外观是

A．白色片

B．黄色片

C．绿色片

D．红色片

E．棕色片