Without regular supplies of some hormones our capacity to behave would be seriously impaired; without others we would soon die. Tiny amounts of some hormones can modify moods and actions, our inclination to eat or drink, our aggressiveness or submissiveness, and our reproductive and parental behavior. And hormones do more than influence adult behavior; early in life they help to determine the development of bodily form and may even determine an individual’s behavioral capacities. Later in life the changing outputs of some endocrine glands and the body’s changing sensitivity to some hormones are essential aspects of the phenomena of aging.
Communication within the body and the consequent integration of behavior were considered the exclusive province of the nervous system up to the beginning of the present century. The emergence of endocrinology as a separate discipline can probably be traced to the experiments of Bayliss and Starling on the hormone secretion. This substance is secreted from cells in the intestinal walls when food enters the stomach; it travels through the bloodstream and stimulates the pancreas to liberate pancreatic juice, which aids in digestion. By showing that special cells secret chemical agents that are conveyed by the bloodstream and regulate distant target organs or tissues. Bayliss and starling demonstrated that chemical integration could occur without participation of the nervous system.
The term “hormone” was first used with reference to secretion。 Starling derived the term from the Greek hormone, meaning “to excite or set in motion。 The term “endocrine” was introduced shortly thereafter “Endocrine” is used to refer to glands that secret products into the bloodstream。 The term “endocrine” contrasts with “exocrine”, which is applied to glands that secret their products though ducts to the site of action。 Examples of exocrine glands are the tear glands, the sweat glands, and the pancreas, which secrets pancreatic juice through a duct into the intestine。 Exocrine glands are also called duct glands, while endocrine glands are called ductless。
1.What is the author’s main purpose in the passage?
A.To explain the specific functions of various hormones.
B.To provide general information about hormones.
C.To explain how the term “hormone” evolved.
D.To report on experiments in endocrinology.
2。The passage supports which of the following conclusions?
A.The human body requires large amounts of most hormones.
B.Synthetic hormones can replace a person’s natural supply of hormones if necessary.
C.The quantity of hormones produced and their effects on the body are related to a person’s age.
D.The short child of tall parents very likely had a hormone deficiency early in life.
3。It can be inferred from the passage that before the Bayliss and Starling experiments, most people believed that chemical integration occurred only___。
B。in the endocrine glands。
C.under control of the nervous system.
D.during strenuous exercise.
4.The word “liberate” could best be replaced by which of the following?
A.Emancipate B.Discharge C.Surrender D.Save
5.According to the passage another term for exocrine glands is___.
If the old maxim that the customer is always right still has meaning, then the airlines that ply the world’s busiest air route between London and Paris have a flight on their hands。
The Eurostar train service linking the UK and French capitals via the Channel Tunnel is winning customers in increasing numbers。 In late May, it carried its one millionth passenger, having run only a limited service between London, Paris and Brussels since November 1994, starting with two trains a day in each direction to Paris and Brussels。 By 1997, the company believes that it will be carrying ten million passengers a year, and continue to grow from there。
From July, Eurostar steps its service to nine trains each way between London and Paris, and five between London and Brussels。 Each train carries almost 800 passengers, 210 of them in first class。
The airlines estimate that they will initially lose around 15%-20% of their London-Paris traffic to the railways once Eurostar starts a full service later this year (1995), with 15 trains a day each way. A similar service will start to Brussels. The damage will be limited, however, the airlines believe, with passenger numbers returning to previous levels within two to three years.
In the short term, the damage caused by the 1 million people-levels traveling between London and Paris and Brussels on Eurostar trains means that some air services are already suffering. Some of the major carriers say that their passenger numbers are down by less than 5% and point to their rivals-Particularly Air France-as having suffered the problems. On the Brussels route, the railway company had less success, and the airlines report anything from around a 5% drop to no visible decline in traffic.
The airlines’ optimism on returning traffic levels is based on historical precedent. British Midland, for example, points to its experience on Heathrow Leeds Bradford service which saw passenger numbers fold by 15% when British Rail electrified and modernized the railway line between London and Yorkshire. Two years later, travel had risen between the two destinations to the point where the airline was carrying record numbers of passengers.
1。British airlines confide in the fact that__。
A.they are more powerful than other European airlines.
B.their total loss won’t go beyond a drop of 5% passengers.
C.their traffic levels will return in 2-3 years.
D.traveling by rail can never catch up with traveling by air.
2。The author’s attitude towards the drop of passengers may be described as__。
3。In the passage, British Rail (Para 6) is mentioned to__。
A.provide a comparison with Eurostar.
B.support the airlines’ optimism.
C.prove the inevitable drop of air passengers.
D。call for electrification and modernization of the railway。
4.The railway’s Brussels route is brought forth to show that__.
A。the Eurostar train service is not doing good business。
B。the airlines can well compete with the railway。
C.the Eurostar train service only caused little damage.
D。only some airlines, such as Air France, are suffering。
5.The passage is taken from the first of an essay, from which we may well predict that in the following part the author is going to__.
A.praise the airlines’ clear-mindedness.
B。warn the airlines of high-speed rail services。
C.propose a reduction of London/Paris flights.
D。advise the airlines to follow British Midland as their model。