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 (球體). Astronomers (天文學(xué)家)think that at the center of a black hole there is a single point in space with infinite (無(wú)限的)density (稠密). This single point is called a singularity (奇點(diǎn)). 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(視界)only 18 miles across.

-- The nearest black holes would be dozens of light years away from Earth. One light year is about 6 trillion(萬(wàn)億)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

根據(jù)下面材料，回答題。

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 (球體). Astronomers(天文學(xué)家) think that at the center of a black hole there is a single point in space with infinite (無(wú)限的) density (稠密). This single point is called a singularity (奇點(diǎn)). 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 (視界) only 18 miles across.

？ The nearest black holes would be dozens of light years away from Earth. One light year is about 6 trillion (萬(wàn)億) 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

請(qǐng)根據(jù)短文內(nèi)容，回答題。

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 (球體). Astronomers(天文學(xué)家) think that at the center of a black hole there is a single point in space with infinite (無(wú)限的 ) density (稠密 ) . This single point is called a singularity (奇點(diǎn)). 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.＜br＞

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

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

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

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 (視界) only 18 miles across.＜br＞

The nearest black holes would be dozens of light years away from Earth. One light year is about 6 trillion (萬(wàn)億) miles. Even the most powerful telescopes could not pick out an object so small at such a great distance.＜br＞

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

A.dense

B.compressed

C.concentrated

D.closed

A) dark

B) dense

C) black

D) bold

realm magic charter angle steer highlight curve

skim annoy veil dense stoop overhead dense

Some species of birds are highly sociable and nest in dense colonies.

A．hardly

B．seasonably

C．extremely

D．chiefly

When the lorry drove past, the exhaust pipe belched dense petrol fumes.

A．showed

B．sent

C．brought

D．produced

The giant trees above the dense canopy layer(樹冠層) cannot enjoy sunlight.

A．Y

B．N

C．NG

A．There are 200 vehicles for every kilometer of roadway.

B．It has a dense population.

C．There are many museums and palaces.

D．It has many towering buildings.

There are dense forests all over the tropical regions.

A．Y

B．N

C．NG