翻译：By making vehicles lighter in weight aluminum has greatly reduced the amount of fuel needed to move them, （Passage Two）

to separate from the ores(矿石) in which it was found that its price was higher than that of gold. The price remained high until a new process was discovered for refining the metal with the aid of electricity approximately three quarters of a century later. The new method was so much cheaper that aluminum became practical for many purposes, one of which was making pots and pans.

Aluminum is lightweight, rustproof and easily shaped into different forms. By mixing it with other metals, scientist have been able to produce a variety of alloys, some of which have the strength of steel but weigh only one third as much.

Today, the uses of aluminum are innumerable. Perhaps its most important use is in transportation. Aluminum is found in the engines of automobiles, in the hulls of boats. It is also used in many parts of airplanes. In fact, the huge "airbus" planes would probably never have been produced if aluminum did not exist. By making vehicles lighter in weight aluminum has greatly reduced the amount of fuel needed to move them. Aluminum is also being used extensively in the building industry in some countries.

Since aluminum is such a versatile(多用的) metal, it is fortunate that bauxite(铝土矿) , which is one of its chief sources, is also one of the earth's most plentiful substances. As the source of aluminum is almost inexhaustible, we can expect that more and more uses will be found for this versatile metal.

The price of aluminum was sharply reduced when people discovered a new refining process with the aid of______.

A．wind power

B．solar energy

C．hydraulic power

D．electricity

In order to escape from the earth, a heavier object ______.

A．demands a greater initial speed than a lighter one

B．demands as great an initial speed as a lighter one

C．must be made lighter than its original weight

D．has to overcome a greater gravity than a lighter one

An advantage of aluminum pistons, when compared to cast iron pistons is _____.

A.greater high temperature strength

B.better heat conductivity

C.greater weight per cubic inch

D.increased resistance to wear

The advantage(s) of using wire rope lashing on vehicles aboard Ro-Ro vessels is that it__.

A.is lighter than chain

B.has a good working life

C.is not affected by temperature

D.All of the above

lighter.

A．Y

B．N

C．NG

Succeeding in a job interview starts with making a good impression.(翻译)

To reduce weight, plastic has taken ______ of iron and steel in making boats.

A．its place

B．place

C．the, place

D．a place