In the US, people prefer waiting for a table to sitting with people they don’t know. If you are sitting at a table with people you don’t know, it is impolite to light up a cigarette without asking if it will disturb them.
At American restaurants and coffee shops you are usually served tap water (自来水) before you order. You may find bread and butter is free, and if you order coffee, you may get a free refill（续杯）.
Most cities and towns have no rules about opening and closing time for stores or restaurants, though they usually do make rules for bars. Especially in large cities, stores may be open 24 hours a day.
Serving (一份) in restaurants is often large, too large for many people. If you can’t finish your meal but would like to enjoy the food later, ask your waitress or waiter for a “doggie bag”. It may have a picture of a dog on it, but everybody knows you’re taking the food for yourself.
Supper and dinner are both words for the evening meal. Some people have “Sunday dinner”. This is an especially big noon meal.
Tips are not usually added to the check. They are not included in the price of the meal, either. A tip of about 15% is expected and you should leave it on the table when you leave. In some restaurants, a check is brought on a plate and you put your money there. Then the waiter or waitress brings you your change.
【小题1】Which of the following statements is true?

BEING an astronaut sounds cool, doesn't it? In space, they get to do some pretty amazing things, like floating in zero gravity(重力).
However, there are also plenty of things that astronauts can't do because of their weightless environment, and that's very sad. What's worse, they can't even let their sadness show, because it's impossible to cry in zero gravity.
Of course, astronauts can still produce tears. But crying is much more difficult in space, according to The Atlantic(大西洋月刊) in January. Without gravity, tears don't flow(流动) down out of the eyes like they do here on Earth. This means that when you cry in space, your tears have nowhere to go-they just stick(粘) to your eyes.
In May 2011, astronaut Andrew Feustel experienced this during one of his spacewalks. "Tears," he said, "don't fall off of your eyes...They just kind of stay there."
Besides making your vision(视线)unclear, this can also cause physical pain. Back on Earth, tears are supposed to bring comfort to the eyes. But that's not the case in space. The space environment dries out astronauts' eyes, and when tears suddenly wet the eyes, it can cause pain rather than comfort. "My right eye is stinging(刺痛) like crazy," Feustel told his teammate during the walk.
Since gravity doesn't work in space, astronauts need some extra help to get rid of（除去） the tears. Feustel chose to rub his eyes against his helmet to wipe(擦) the tears away. Another choice is to just wait-"When the tears get big enough they simply break free of the eyes and float around," astronaut Ron Parise told The Atlantic.
There are lots of small things-things like crying-that we are so used to on Earth. We usually take them for granted until they become a problem in a totally different environment, like space.  There, astronauts can't talk to each other directly. They also can't eat or drink in normal ways. They can't even burp (打嗝), because there is no gravity to hold the food down in their stomach. If they do burp, they just end up throwing up（呕吐）everything in their stomach, according to the UK National Space Center.
Therefore, perhaps it's only space explorers who can honestly say: "Gravity, you're the best."
【小题1】From Paragraphs 2 and 3 , we can know that_______.