题目内容
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Such electron tubes ______ in a radio set are also found in a TV set.
A．that we use
B．as we use
C．as we use them
D．that we use them
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5 The directors of Blaina Packaging Co (BPC), a well-established manufacturer of cardboard boxes, are currently
considering whether to enter the cardboard tube market. Cardboard tubes are purchased by customers whose
products are wound around tubes of various sizes ranging from large tubes on which carpets are wound, to small
tubes around which films and paper products are wound. The cardboard tubes are usually purchased in very large
quantities by customers. On average, the cardboard tubes comprise between 1% and 2% of the total cost of the
customers’ finished product.
The directors have gathered the following information:
(1) The cardboard tubes are manufactured on machines which vary in size and speed. The lowest cost machine is
priced at $30,000 and requires only one operative for its operation. A one-day training course is required in order
that an unskilled person can then operate such a machine in an efficient and effective manner.
(2) The cardboard tubes are made from specially formulated paper which, at times during recent years, has been in
short supply.
(3) At present, four major manufacturers of cardboard tubes have an aggregate market share of 80%. The current
market leader has a 26% market share. The market shares of the other three major manufacturers, one of which
is JOL Co, are equal in size. The product ranges offered by the four major manufacturers are similar in terms of
size and quality. The market has grown by 2% per annum during recent years.
(4) A recent report on the activities of a foreign-based multinational company revealed that consideration was being
given to expanding operations in their packaging division overseas. The division possesses large-scale automated
machinery for the manufacture of cardboard tubes of any size.
(5) Another company, Plastic Tubes Co (PTC) produces a narrow, but increasing, range of plastic tubes which are
capable of housing small products such as film and paper-based products. At present, these tubes are on average
30% more expensive than the equivalent sized cardboard tubes sold in the marketplace.
Required:
(a) Using Porter’s five forces model, assess the attractiveness of the option to enter the market for cardboard
tubes as a performance improvement strategy for BPC. (10 marks)
The clock had stopped because Winthrop had put some long glass tubes he was using for an experiment into the box for safekeeping. The quake had knocked the tubes over and blocked the pendulum. Winthrop, therefore, had the exact time that the earthquake had hit Boston. He looked at the key on the floor. The quake had thrown it forward in the direction of the quake's motion by a shock coming from the northwest, perhaps in Canada.
This passage suggests that ______.
A．John Winthrop had difficulty in sleeping
B．earthquakes are common in Boston
C．Boston was a center for clock-making
D．John Winthrop was a scientist
A.It heips exchange water and chemicals between the blood and thetissues,它有助于在血液和组织之间交换水和化学物质。
B.it forms a cosed circuit of hollow tubes that allow blood to be transported to and from the heart.它形成了空心管的封闭循环，可以将血液输送到心脏和从心脏输送。
C.It carries blood away from the heart.它将血液带离心脏。
D.It prevents backflow or spillage of blood back into the chambers.它可以防止血液回流或溢出到腔室。
More than 40 years passed before physicists were able to offer an explanation for superconductivity. The accepted theory, developed in the 1950s, holds that the fundamental behavior. of electrons changes at very low temperatures because of the effects of quantum mechanics. Electrons are tiny particles that make up the outer part of an atom, circling rapidly around the nucleus of the atom. In a regular conductor—a metal that conducts an electric current—the outermost electrons are not bound tightly to the atoms, and so they move around relatively freely. The flow of these electrons is an electric current.
At normal temperatures, a conductor's electrons cannot move completely freely through the metal because they are "bumped around" by the metal's atoms. But according to the leading theory of superconductivity, when a metal is very cold, electrons form. pairs. Then, like couples maneuvering on a crowded dance floor but never colliding, the paired electrons are able to move unimpeded through the metal. In pairing up, it seems, the electrons are able to "blend together" and move in unison without resistance. This explanation seems to account for superconductivity at extremely low temperatures, but in 1986 scientists in Switzerland found that some metal-containing ceramics are superconductors at much higher temperatures. By 1992, scientists had developed ceramics that become superconducting at - 297'F, and some researchers speculated that room-temperature superconductors may be possible. Scientists are still trying to formulate a theory for high-temperature superconductivity.
The new ceramic materials can be maintained at their superconducting temperatures, with relatively inexpensive liquid nitrogen rather than the much colder and much more costly liquid helium required by metal superconductors. The cost difference could make superconductivity practical for many new technologies. For example, magnetically levitated trains, which require superconducting electromagnets, would be much cheaper to build than they are now. Superconducting devices might also be used for advanced power transmission lines and in new types of compact, ultrafast computers. But for the time being, superconductivity is finding application mostly in scientific research and in some kinds of medical imaging devices.
The flow of an electric current in a regular conductor is made possible by the fact that______.
A．electrons circle rapidly around the atom
B．the outermost electron move relatively freely around the atom
C．the innermost electrons stick to the atom
D．the outermost electrons are bound tightly to the inner ones
A.the overtreatment for dying patients
B.the different attitude of doctor and patients toward death
C.the disproportionately high medicare expenditure in America
D.the unequal and non．transparent doctor—patient relationship
