单选题All living creature are thought to ______ an organism that came into being three billion years ago.A descend toB descend onC descend intoD descend from

Giant pandas are on the verge of extinction.

A:getting ill
B:living on
C:dying out
D:being hungry

共用题干
第三篇

Pool Watch

Swimmers can drown in busy swimming pools when lifeguards fail to notice that they are
in trouble.A report says that on average 15 people drown in British pools each year,but
many more suffer major injury after getting into difficulties.Now a French company has
developed an artificial intelligence system called Poseidon that sounds the alarm when it
sees someone in danger of drowning.
When a swimmer sinks towards the bottom of the pool,the new system sends an alarm
signal to a poolside monitoring station and a lifeguard's pager（呼机）.In trials at a pool in
Ancenis,near Nantes,it saved a life within just a few months,says Alistair McQuade,a
spokesman for its maker,Poseidon Technologies.
Poseidon keeps watch through a network of underwater and overhead video cameras.
Al software analyses the images to work out swimmers' trajectories（轨迹）.To do this
reliably,it has to tell the difference between a swimmer and the shadow of someone being
cast onto the bottom or side of the pool.
It does the same with an image from another camera viewing the shape from a different
angle.If the two projections are in the same position,the shape is identified as a shadow
and is ignored.But if they are different,the shape is a swimmer and so the system follows
its trajectory.
To pick out potential drowning victims,anyone in the water who starts to descend
slowly is added to the software's"pre-alert"（预先警戒）list,says McQuade. Swimmers
who then stay immobile on the pool bottom for 5 seconds or more are considered in danger
of drowning.Poseidon double-checks that the image really is of a swimmer,not a shadow,
by seeing whether it obscures（使模糊）the pool's floor texture when viewed from overhead.
If so,it alerts the lifeguard,showing the swimmer's location on a poolside screen.
The first full-scale Poseidon system will be officially opened next week at a pool in High
Wycombe,Buckinghamshire.One man who is impressed with the idea is Travor Baylis,
inventor of the clockwork（时钟装置）radio. Baylis runs a company that installs swimming
pools-and he was once an underwater escapologist（脱身杂技演员）with a circus（马
戏团）."I say full marks to them if this works and can save lives,"he says.

To save a life,Al software must be able to
A:descend in the water.
B:videotape every movement.
C:distinguish between a swimmer and a shadow.
D:save a life within a few months.

We derive information mainly from the Internet.

A:deprive
B:obtain
C:descend
D:trace

Giant pandas are on the verge of extinction

A:getting ill
B:living on
C:dying out
D:being hungry

There are many stereotypes about the character of people in various parts of the United States．In the Northeast and Midwest,people are said to be closed and private．In the South and West,however,they are often thought of as being more open and hospitable．Ask someone from St．Louis where the nearest sandwich shop is,and he or she will politely give you directions．A New Yorker might eye you at first and after deciding it is safe to talk to you,might give you a rather unexpected explanation．A person from Georgia might be very kind about directing you and even suggest some different places to eat．A Texan just might take you to the place and treat you to lunch.
American stereotypes are abundant．New Englanders are often thought of as being friendly and helpful．Southerners are known for their hospitality and warmth．People from the western part of the United States are often considered very outgoing．These differences in character can be traced to different factors such as climate,living conditions,and historical development.
When travelling from place to place,Americans themselves are often surprised at the differing degrees of friendliness in the United States.

New Englanders are often thought of as being__.

A.hospital and warm
B.out going
C.friendly and helpful
D.all of the above