An internet is a combination of networks connected by （1). When a datagram goes from a sou

rce to a? (2), it will probably pass many (3) until it reaches the router attached to the destination network. A router receives a? (4) from a network and passes it to another network. A router is usually attached to several networks. When it receives a packet, to which network should it pass the packet? The decision is based on optimization: Which of the available (5) is the optimum pathway?

空白（5）处应选择（）

A. pathways

B. routers

C. diagrams

D. calls

rce to a? (2), it will probably pass many (3) until it reaches the router attached to the destination network. A router receives a? (4) from a network and passes it to another network. A router is usually attached to several networks. When it receives a packet, to which network should it pass the packet? The decision is based on optimization: Which of the available (5) is the optimum pathway?

空白（4）处应选择（）

A. destination

B. resource

C. packet

D. source

rce to a? (2), it will probably pass many (3) until it reaches the router attached to the destination network. A router receives a? (4) from a network and passes it to another network. A router is usually attached to several networks. When it receives a packet, to which network should it pass the packet? The decision is based on optimization: Which of the available (5) is the optimum pathway?

空白（3）处应选择（）

A. destinations

B. routers

C. packets

D. computers

An internet is a combination of networks connected by (71) .When a datagram goes from a source to a (72) ，it will probably pass many (73) until it reaches the router attached to the destination network．A router receives a (74) from a network and passes it to another network．A router is usually attached to several networks．When it receives a packet，to which network should it pass the packet? The decision is based on optimization： Which of the available (75) is the optimum pathway?

A．modems

B．routers

C．switches

D．computers

An internet is a combination of networks connected by (71) .When a datagram goes from a source to a (72) ，it will probably pass many (73) until it reaches the router attached to the destination network．A router receives a (74) from a network and passes it to another network．A router is usually attached to several networks．When it receives a packet，to which network should it pass the packet? The decision is based on optimization： Which of the available (75) is the optimum pathway?

A．modems

B．routers

C．switches

D．computers

● An internet is a combination of networks connected by （71） . When a datagram goes from a source to a （72） , it will probably pass many （73） until it reaches the router attached to the destination network. A router receives a （74） from a network and passes it to another network. A router is usually attached to several networks. When it receives a packet, to which network should it pass the packet? The decision is based on optimization: Which of the available （75） is the optimum pathway?

（71）

A. modems

B. routers

C. switches

D. computers

（72）

A. user

B. host

C. city

D. destination

（73）

A. destinations

B. routers

C. packets

D. computers

（74）

A. destination

B. resource

C. packet

D. source

（75）

A. pathways

B. routers

C. diagrams

D. calls

● An internet is a combination of networks connected by （71） . When a datagram goes from a source to a （72） , it will probably pass many （73） until it reaches the router attached to the destination network. A router receives a （74） from a network and passes it to another network. A router is usually attached to several networks. When it receives a packet, to which network should it pass the packet? The decision is based on optimization: Which of the available （75） is the optimum pathway?

（71）

A. modems

B. routers

C. switches

D. computers

（72）

A. user

B. host

C. city

D. destination

（73）

A. destinations

B. routers

C. packets

D. computers

（74）

A. destination

B. resource

C. packet

D. source

（75）

A. pathways

B. routers

C. diagrams

D. calls

根据以下资料，回答1~4题。 Many people use wood stoves and fireplaces to heat their homes．Scientists have become worried about the smoke that they give off．Harmful chemicals are in the smoke．The smoke is causing air pollution．The pieces of pollution, called soot, are floating in the air．They are too tiny to see．Scientists must use a microscope to see them. Small amounts of soot are safe, but large amounts can be dangerous．The govenment wants to limit this kind of pollution．It may stop people from using their fireplaces. The air is tested every day．When soot levels are high, more than 65 micrograms of soot per cubic meter, factories must stop making smoke．The government thinks that limit should be much lower. Factories produce the most smoke and soot．But the government thinks that all types of burning should be limited．The soot levels from factories and homes could be limited．Home owners may have to install new wood stoves that they comply with the new law．Or, they may not be able to bum on days when the air quality is bad. Residents of some towns are fined if they violate the burning ban．Scientists hope these new regulations will make the air cleaner and less harmful to breathe. Why is it dangerous to burn too much wood? A．The fire could burn you. B．It's not healthy to be too warm. C．Harmful chemicals are released in the soot. D．The smoke is filled with unseeable tiny pieces.

听力原文： Current studies show that what goes on labels is an important consideration for manufacturers, since more than seventy percent of shoppers read food labels when considering whether to buy a product.

A recent controversy as to whether labels on prepared foods should educate or merely inform. the consumer is over, and a consumer group got its way. The group had maintained that product labels should do more than simply list how many grams of nutrients a food contains. Their contention was that labels should also fist the percentage of a day's total nutrients that the product will supply to the consumer, because this information is essential in planning a healthy diet.

A government agency disagreed strongly, favoring label that merely informs the consumer, in other words, a label that only lists the contents of the product. The agency maintained that consumers could decide for themselves if the food is nutritious and is meeting their daily needs.

The consumer group, in supporting its case, had cited a survey in which shoppers were shown a food label, and were then asked if they would need more or less of a certain nutrient after eating a serving of this product. The shoppers were not able to answer the questions easily when they were not given a specific percentage.

This study, and others helped get the new regulation passed, and now food products must have the more detailed labels.

(33)

A．Less than 68%.

B．About 50%.

C．Over 70%.

D．Around 45%.

听力原文： Current studies show that what goes on labels is an important consideration for manufacturers, since more than seventy percent of shoppers read food labels when considering whether to buy a product.

A recent controversy as to whether labels on prepared foods should educate or merely inform. the consumer is over, and a consumer group got its way. The group had maintained that product labels should do more than simply list how many grams of nutrients a food contains. Their contention was that labels should also list the percentage of a day's total nutrients that the product will supply to the consumer, because this information is essential in planning a healthy diet.

A government agency disagreed strongly, favoring label that merely informs the consumer, in other words, a label that only lists the contents of the product. The agency maintained that consumers could decide for themselves if the food is nutritious and is meeting their daily needs.

The consumer group, in supporting its case, had cited a survey in which shoppers were shown a food label, and were then asked if they need more or less of a certain nutrient after eating a serving of this product. The shoppers were not able to answer the questions easily when they were not given a specific percentage.

This study, and others helped get the new regulation passed, and now food products must have the more detailed labels.

32．According to the speaker, how many percent of customers read food labels before making a purchase?

What was the controversy about?

What's the government agency's attitude towards more detailed labeling?

What kind of food labels will be provided to the customers now?

(33)

A．Around 45%.

B．About 50%.

C．Less than 68%.

D．Over 70%.