Redwood trees are the tallest plants on the earth,reaching heights of up to 100 meters.They are also known for their longevity,typically 500 to 1000 years,but sometimes more than 2000 years.A hundred million years ago,in the age of dinosaurs,redwoods were common in the forests of a much more moist and tropical North America.As the climate became drier and colder,they declined to a narrow strip along the Pacific coast of Northern Califomia. The trunk of redwood trees is very strong and usually forms a single straight column.It is covered with a soft bark.This bark can be pretty thick,well over two feet in the more mature trees.It gives the older trees a certain kind of protection from insects,but the main benefit is that it keeps the center of the tree harmless from moderate forest fires because of its thickness.This fire resistant quality explains why the giant redwood grows to live that long.While most other types of trees are destroyed by forest fires,the giant redwood actually prospers because of them. Moderate fires will clear the ground of competing plant life,and the rising heat dries and opens the ripe fruit of the redwood,releasing many thousands of seeds onto the ground below. New trees are often produced from shoots,little baby trees,which form at the base of the trunk.These shoots grow slowly,fed by the root system of the "mother'' tree.When the main tree dies,the shoots are then free to grow as full trees,forming a "fairy ring" of trees around the original tree.These trees,in turn,may give rise to more shoots,and the cycle continues. Why were redwood trees easier to find in the forests of North America millions of years ago? A) The trees were taller and stronger. B) The soil was softer for seeds to develop. C) The climate there was warmer and wetter. D) The temperature was lower along the Pacific coast.
C


(Question)
One kind of female butterfly mates only once in its life -- and then closes its wings to avoid _ " when pursued by persistent and unwanted males, a Japanese researcher said. Observations of the Small Copper Butterfly, a colourful orange and black butterfly, showed that some females closed their wings when males flew by, but only when they were males of their own species, said Jun-Ya Ide, an associate professor at Kurume Institute of Technology in Fukuoka, western Japan. "When we looked into why, the males were courting the females. They do this very stubbornly, so the females sometimes try to get away -- or prefer to stay unobserved," he added. Ide and his colleagues brought a model of a male butterfly near the females to test their reactions and found that young females that had yet to mate kept their wings open, but those that had already mated closed them. Not only can the persistent attentions of unwanted suitors harm the delicate females, fleeing from them -- with the male often in pursuit -- uses up strength and can even shorten their lives, he added. "Closing their wings makes them less visible, helping them avoid communication with their own species. We figured they were trying to avoid harassment by males," Ide said. According the the passage, which is correct? A) The females closed their wings when males flew by. B) Only the model of a male butterfly can make the young female butterflies to keep their wings open. C) The female butterfly mates only once in its life D) Not only can the persistent attentions of wanted suitors harm the delicate females, fleeing from them with the male often in pursuit -- uses up strength and can even shorten their lives.
(Answer)
C


Ques: Metro Pocket Guide Metrorail   Each passenger needs a farecard to enter and go out. Up to two children under age five may travel free with a paying customer. Farecard machines are in every station. Bring small bills because there are no change machines in the stations and farecard machines only provide up to $50 in change. Get one day of unlimited Metrorail rides with a One Day Pass. Buy it from a farecard machine in Metro station. Use it after 9:30 a.m. until closing on weekdays, and all day on weekdays and holidays. Hours of service Open: 5 a.m. Mon.--Fri.           7 a.m. Sat.--Sun. Close: midnight Sun.--Thurs.       3 a.m. Fri.--Sat. nights  Last train times vary. To avoid missing the last train, please check the last train times posted in stations. Metrobus When paying with exact change, the fare is $1.35. When paying with a SmarTrip card, the fare is $1.25. Fares for senior/disabled customers Senior citizens 65 and older and disabled customers may ride for half the regular fare. On Metrorail and Metrobus, use a senior/disabled farecard or SmarTrip card. For more information about buying senior/disabled farecard, SmarTrip cards and passes, please visit MetroOpensDoor.com or call 202-637-7000 and 202-637-8000. Senior citizens and disabled customers can get free guide on how to use proper Metrobus and Metrorail services by calling 202-962-1100. Travel tips   Avoid riding during weekday rush periods--before 9:30 a.m. and between 4 and 6 p.m. If you lose something on a bus or train or in a station, please call Lost & Found at 202-96201195. What should you know about farecard machines? A) They start selling tickets at 9:30 a.m. B) They are connected to change machines. C) They offer special service to the elderly. D) They make change for no more than $5.
Ans: D


Like many other small boys, I was fascinated by cars, not least because my oldest brother was a bit of a car guy and subscribed to cool magazines like Car and Driver and Motor Trend. Every so often, one of those magazines would run an article on the "Car of the Future". They featured unconventional styling and things like small nuclear reactors as power sources. Yet, frankly, my car doesn't do anything that my brother's Studebaker didn't do. It goes, it stops, it burns gasoline, it plays music. I still have to steer it, and it still runs into things if I don't steer it carefully. But guess what? All of these things are subject to change in the not-so-distant future. It will still go and stop, but it may not burn gasoline, I may not have to steer it, and it may be a lot better at not running into things. Airbags aren't the be-all and end-all in safety. In fact, considering the recent news about people occasionally being killed by their airbags in low-speed collisions  ,they obviously still need some development. But they aren't going away, and in fact, you can expect to see cars appearing with additional, side-impact airbags, something some European car manufacturers already offer. Better than systems to minimize   injury in the event of an accident, however, are systems that minimize the likelihood of an accident happening in the first place. Future cars may be able to eliminate many of the major causes of accidents, including drunk-driving, tailgating   and sleepiness. Cars could be equipped with sensors that can detect alcohol in a driver's system and prevent the car from being started, for example. Many accidents are caused by people following the car in front too closely. As early as next year, you'll be able to buy cars with radar-equipped control systems. If the radar determines you're closing too quickly with the car in front, it will ease up on the throttle  . For city streets, expect other radar devices that will give advance warning that the car in front of you has slowed abruptly   and you should... According to the author, what will future cars do if the sensors detect alcohol in the driver's system? A) They will give a warning in advance. B) They will brake automatically. C) They will ease up on the throttle. D) They will not start.

D