简述苯乙胺类肾上腺素能激动剂的构效关系。

阅读理解。

     "An apple a day keeps the doctor away." Well, milk may work in the same way!

     Milk is the natural food for mammalian (哺乳动物) babies. It helps them grow strong because it is rich

in protein (蛋白质), calcium (钙) and vitamins. Milk can also help you sleep better because it calms you

down.

     But remember to drink milk with care. Find out how old the milk is. Make sure it is fresh and hasn't gone

bad. Don't drink milk when your stomach is empty. Eat some bread or corn at the same time. That'll help

you take in more protein and vitamins.

     Doctors say teens need at least 500ml of milk a day. That's two or three cups. Milk-drinking started long

ago, as early as 6,000-8,000BC. At that time people started to keep cows, sheep and goats to get their milk.

Of course what you drink today isn't that fresh from the cow. People cool the fresh milk down to 40℃ to

stop the bacteria (细菌)growing. In factories, milk is pasteurized (灭菌) to stop it growing bad. After

disinfections (消毒) and packaging, it goes to the supermarkets.

     Yoghourt also comes from milk. People make some special bacteria to change the taste of milk and

make the nutrients (营养) in it easier for people to take in. Maybe that's why it's getting more popular

with people!

1. Milk helps people grow strong because it is rich in _____. [ ]

A. Calcium

B. protein

C. vitamins

D. A, B and C

2. The sentence "An apple a day keeps the doctor away." tells us that _____. [ ]

A.the doctor likes to eat apples every day

B. the doctor doesn't like apples at all

C. the doctor eats an apple each day

D. apples are good for our health

3. When you drink milk, you'd better _____. [ ]

A. find out when the milk was produced

B. make sure it's fresh and hasn't gone bad

C. not drink milk when your stomach is empty

D. do all of the above

4. Why is it better to eat some bread or corn while drinking milk?  [ ]

A. Our body can take in more protein and vitamins in this way.

B. That'll help us grow taller and stronger.

C. That'll help us taste milk better.

D. We'll still feel hungry without eating some bread or corn. 

5. Which of the following statements is true? [ ]

A. One cup of milk is good enough for teens each day.

B. Drinking milk is likely to make teens sleepy.

C. To stop the bacteria growing, people cool the fresh milk down to 40℃.

D. Yoghourt is one kind of milk which has gone bad

如图所示的光路图中，能正确表示光从空气射入水中时发生的反射和折射现象是 [ ]

A.

B.

C.

D.

束颤不会出现于（）

A.正常人小腿三头肌

B.脊髓前角细胞病

C.厌氧菌感染

D.甲状腺毒症

E.周围性神经损伤

[A] Market Data
[B] Market Prosperity
[C] Secret of Success
[D] Questions to Ask
[E] Understanding Your Market
[F] Market Research
Successful small business expansions and new job formation lead the way in creating new markets, innovations and jobs that fuel economic growth and prosperity.
In recognition of the importance of small business to a p economy, the U. S. Small Business Administration (SBA) is pleased to help meet the information needs of existing business owners and aspiring entrepreneurs.
41. ______
Your business will not succeed just because you want it to succeed. Determining if there is a market for your products or services is the most critical item of planning. Once you decide on your product or service, you must analyze your market--a process involving interviewing competitors, suppliers and new customers.
Before you begin researching your market, however, you should take a brief, but close, look at your product or service from an objective standpoint. You should ask yourself the following questions:
-- Is this product or service in constant demand
-- How many competitors provide the same service or product
-- Can I create a demand for my product or service
-- Can I compete effectively in price, quality and delivery
—Can I price my product or service to assure a profit
Once you are satisfied that these preliminary questions are answered, move on to performing your research.
42. ______.
It is extremely beneficial to investigate a market because the information gathered can increase your profit potential. Specifically, it:
-- Indicates alternative sales approaches to your market.
-- Provides a more accurate base for making profit assumptions.
-- Aids in the organization of marketing activities.
-- Assists in the development of critical short/mid-term goals.
-- Helps establish your market’s profit boundaries.
Unfortunately, many entrepreneurs fail to complete this critical section of their business plan. Collecting research data can be frustrating unless you have defined your goals and organized the collection and analysis process. To prevent this from happening, you must plan how you will collect, sort and analyze the information. Maintain a notebook and file in which to store, organize and retrieve data as needed.
43. ______.
Your research should ask these questions..
-- Who are your customers
-- Where are they located
-- What are their needs and resources
-- Is your service or product essential in their operations pr activities
— Can the customer afford your service or product
— Where can you create a demand for your service or product
-- What areas within your market are declining or growing
-- What is the general economy of your service or product area
44. ______.
Knowing your market requires an understanding not only of your product, but also of your customers’ socioeconomic characteristics. This information will serve as a map in letting you know what is ahead.
More market information can be found in,
-- Library listings of trade associations and journals.
-- Regional planning organizations’ studies on growth trends.
-- Banks, realtors and insurance companies.
—Competitors.
-- Customer surveys in your market area.
Once you have obtained and analyzed this information, it will become the foundation of your business plan. Research information is important because it supports the basic assumptions in your financial projection--your reason for going into business.
45. ______
To be successful, a small business owner must know the market. Market research is simply an orderly, objective way of learning about people--the people who will buy from you.

创建对象数组时，对数组的每一个元素都将调用一次构造函数，如果没有显式给出数组元素的初值，则调用缺省的构造函数。下列程序涉及到对象数组的创建和单个对象的创建其输出结果是【 】。 #include using namespace std； class Foo{public： Foo(int x){out<<′A′}Foo(){}} ； Int main(){Foo f[3]，g(3)； retum 0； }