—I don’t suppose they could have finished their experiment,      they?

—       , they are still doing it in the lab.

       A．could; Yes B．didn’t; No C．have; No   D．couldn’t; Yes

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

—I don't suppose he could have done well in the exam last week, _______ he?

—_______,he almost failed to pass the exam.?

A. had; Yes    B. has; No      C. couldn't; Yes      D. did; No

—Do you think David will fail in the maths exam again?

—_________.

A．No, I don’t believe it   B．I hope not

C．I expect not                                                D．I don’t suppose it

—I don’t suppose Jimmy could have done well in the mid-term exam last week,______?

--- ______ he almost failed in the exam．

A．had he; Yes       B．did he ; No         C．do  I ;  Yes       D．could  I ; No