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【单选题】
Passage FiveLaser-doppler radar （）
A．measures the movements of a spaceship by means of light beam
B．makes use of microwaves
C．makes use of sound waves
D．Both A and B
B．makes use of microwaves
C．makes use of sound waves
D．Both A and B
A.
Passage Five
B.
A new kind of radar has been developed for spaceship travelers. A working laboratory model of a new system of radar that makes use of a beam of light is said to be ten thousand times more accurate than the best comparable system of radar that used microwaves.
C.
The model has shown that this radar system, known as laser-doppler radar, can measure with absolute precision speeds varying from spaceship orbital injection (进入) velocities (速度) of five miles per second down to virtual stops--speeds of less than one ten thousandth of an inch per second. According to the scientists who are developing this system, such fine measures of velocity are of prime importance in space missions. In a rendezvous (对接) between two spaceships, or in a landing approach by a vehicle onto an orbiting space station, a bump could rip open a ship’s skin, or a nudge could knock the station out of its orbit.
D.
The light-beam radar, which operates at a frequency of trillions (百万兆) of cycles per second, could easily detect and measure the movement of a vehicle edging up to a satellite space station. A control system using so precise a signal as this would allow a huge vehicle to dock at a space station as lightly as a feather.
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【单选题】根管充填时紧密的充填材料应位于
A.
根尖(rootapex)
B.
根尖孔(apicalforamen)
C.
根尖牙骨质牙本质交界(cemento～ dentinaljunction)
D.
根尖分歧(apicalramification)
E.
根尖1/3处
【单选题】根尖切除术的适应证不包括
A.
根尖周囊肿
B.
根尖周病变广泛
C.
根折伴根尖断端移位，死髓
D.
根管内治疗器械折断出根尖孔
E.
根管充填完善而根尖周病变久治不愈
【单选题】She can not（）her mother again, because she shouted at her all day long.
A.
keep up with
B.
catch up with
C.
put up with
D.
take up with
【单选题】After the passage the author will talk about______.
A.
the principles of designing lenses
B.
techniques of making contact lenses
C.
the design of photographic lenses
D.
styles of lenses
【单选题】25（） A．itself B．themselves C．it D．its
A.
A recent development is the local area network (LAN). (21) its name implies, it serves a local area-possibly as small as a single room, typically an area like an university campus or the premises of a particular business. Local area networks were developed to (22) a need specific to microcomputers the sharing of expensive resources. Microcomputers are cheap, but highcapacity disc stores, fast and/or good quality printers, etc. are expensive. The object of the LAN is to allow (23) microcomputers shared access to these expensive resources, since the microcomputers are cheap, it is a necessary feature of a LAN that the method of connection to the network, and the network hardware (24) , must also be cheap.
B.
A local area network links a number of computers and a number of servers which provide communal facilities, e. g. file storage. (A server usually includes a small microprocessor for control purposes. ) The computers and servers are known as stations. There are two methods of (25) in common use, rings and broadcast networks.
C.
In the ring method( often called a Cambridge Ring) all the stations are linked in a ring, (26) includes one special station, the monitor station.
D.
In broadcast networks, all the stations are (27) to a single linear cable(usually coax cable), and any transmission will be received by all stations.
E.
(28) technology is used, local area networks are a development of the greatest importance. (29) as programming is simplified by an approach that thinks in terms of small procedures or programs, each doing a well-defined job, the computer system of tomorrow is likely to be (30) lots of small systems, each doing a specific job, linked by a local area network.
相关题目：
【单选题】根管充填时紧密的充填材料应位于
A.
根尖(rootapex)
B.
根尖孔(apicalforamen)
C.
根尖牙骨质牙本质交界(cemento～ dentinaljunction)
D.
根尖分歧(apicalramification)
E.
根尖1/3处
【单选题】根尖切除术的适应证不包括
A.
根尖周囊肿
B.
根尖周病变广泛
C.
根折伴根尖断端移位，死髓
D.
根管内治疗器械折断出根尖孔
E.
根管充填完善而根尖周病变久治不愈
【单选题】She can not（）her mother again, because she shouted at her all day long.
A.
keep up with
B.
catch up with
C.
put up with
D.
take up with
【单选题】After the passage the author will talk about______.
A.
the principles of designing lenses
B.
techniques of making contact lenses
C.
the design of photographic lenses
D.
styles of lenses
【单选题】25（） A．itself B．themselves C．it D．its
A.
A recent development is the local area network (LAN). (21) its name implies, it serves a local area-possibly as small as a single room, typically an area like an university campus or the premises of a particular business. Local area networks were developed to (22) a need specific to microcomputers the sharing of expensive resources. Microcomputers are cheap, but highcapacity disc stores, fast and/or good quality printers, etc. are expensive. The object of the LAN is to allow (23) microcomputers shared access to these expensive resources, since the microcomputers are cheap, it is a necessary feature of a LAN that the method of connection to the network, and the network hardware (24) , must also be cheap.
B.
A local area network links a number of computers and a number of servers which provide communal facilities, e. g. file storage. (A server usually includes a small microprocessor for control purposes. ) The computers and servers are known as stations. There are two methods of (25) in common use, rings and broadcast networks.
C.
In the ring method( often called a Cambridge Ring) all the stations are linked in a ring, (26) includes one special station, the monitor station.
D.
In broadcast networks, all the stations are (27) to a single linear cable(usually coax cable), and any transmission will be received by all stations.
E.
(28) technology is used, local area networks are a development of the greatest importance. (29) as programming is simplified by an approach that thinks in terms of small procedures or programs, each doing a well-defined job, the computer system of tomorrow is likely to be (30) lots of small systems, each doing a specific job, linked by a local area network.
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