Virtue is the root whereas ___________ is the branch.

Live is to Evil just as 5423 is to______.

According to this text, "anti-globalization" is to "liberation" as

A．security is to "threats".

B．monopoly is to "competition".

C．publicity is to "privacy".

D．research is to "development".

Which word completes the sentence? Controversy is to quarrel as agreement is to ______.

A．joy

B．concord

C．satisfaction

D．agony

According to the 4th paragraph, "Main Street" is to "fleshpots" as

A．reliability is to "illusion".

B．classics is to "pops".

C．modesty is to "luxury".

D．ideals is to "realities".

According to the last paragraph, "paper plates" is to "china" as ______.

A．temporary is to "permanent".

B．radical is to "conservative".

C．functional is to "artistic".

D．humble is to "noble".

Black Holes

Most scientists agree that black holes exist but are nearly impossible to locate. A black hole in the universe is not a solid object, like a planet, but it is shaped like a sphere (球体). Astronomers(天文学家)think that at the center of a black hole there is a single point in space with infinite(无限的)density(稠密). This single point is called a singularity (奇点). If the singularity theory is correct, it means that when a massive star collapses, all the material in it disappears into the singularity. The center of a black hole would not really be a hole at all, but an infinitely dense point. Anything that crosses the black hole is pulled in by its great gravity.

Although black holes do exist, they are difficult to observe. These are the reasons.

-- No light or anything else comes out of black holes. As a result, they are invisible to a telescope.

-- In astronomical terms, black holes are truly. For example, a black hole formed by the collapse of a giant star would have an event horizon(视界)only 18 miles across.

-- The nearest black holes would be dozens of light years away from Earth. One light year is about 6 trillion(万亿)miles. Even the most powerful telescopes could not pick out an object so small at such a great distance.

In 1994 the Hubble Space Telescope provided evidence that black holes exist. There are still answers to be found, however, so black holes remain one of the mysteries of the universe.

Black holes are part of space.

A．Right

B．Wrong

C．Not mentioned

Twelve is to three ______ four is to one.

A．what

B．as

C．that

D．like

根据下面材料，回答题。

Black Holes

Most scientists agree that black holes exist but are nearly impossible to locate. A black hole in the universe is not a solid object, like a planet, but it is shaped like a sphere (球体). Astronomers(天文学家) think that at the center of a black hole there is a single point in space with infinite (无限的) density (稠密). This single point is called a singularity (奇点). If the singularity theory is correct, it means that when a massive star collapses, all the material in it disappears into the singularity. The center of a black hole would not really be a hole at all, but an infinitely dense point.

Anything that crosses the black hole is pulled in by its great gravity.

Although black holes do exist, they are difficult to observe. These are the reasons.

? No light or anything else comes out of black holes. As a result, they are invisible to a telescope.

? In astronomical terms, black holes are truly. For example, a black hole formed by the collapse of a giant star would have an event horizon (视界) only 18 miles across.

? The nearest black holes would be dozens of light years away from Earth. One light year is about 6 trillion (万亿) miles. Even the most powerful telescopes could not pick out an object so small at such a great distance.

In 1994 the Hubble Space Telescope provided evidence that black holes exist. There are still answers to be found, however, so black holes remain one of the mysteries of the universe.

Black holes are part of space. 查看材料

A.Right

B.Wrong

C.Not mentioned

The function of the bypass valve on the self-contained breathing apparatus is to ______．

A.control the pressure of the oxygen as it enters the body

B.allow the wearer to manually give himself oxygen

C.release excess heat which would otherwise cause the bottle to explode

D.allow exhaled gases to pass outside the bottle