42.( )_______ is the second largest
country which has more HIV infection all over the world.
A. China
B. South Africa C.
India D. Thailand
(C)
ars
ago, Mala was a typical middle-class Indian What was it like to live in space?
Imagine
orbiting (环轨道运行) the earth once
every ninety-three minutes. Imagine traveling through space at more than
twenty-seven-thousand kilometers an hour. That is what the skylab astronauts
did. During that time they ate, slept, and did most of the things people do on
the earth. But there was one big difference. There was no gravity.
Gravity is the force that holds us down to the earth. Skylab was
beyond the reach of the earth's gravity. People and objects were weightless.
They floated freely unless held down.
At times, the skylab astronauts enjoyed the 1ack of gravity. They
could float like bubbles through the spaceship. They could hang upside down
like bats(蝙蝠). They could do
sticks like circus acrobats(杂技演员).
At other times, however, they did not enjoy the lack of gravity.
with no gravity, their food new right off the plate. And a dropped tool just
floated away.
Skylab was a space house. But living and working in it were very
different from living and working in a house on the earth.
Skylab had a workshop, a s1eeping area, a kitchen, and a bathroom.
Unlike a bedroom on the earth, the sleeping area did not contain beds. It had
hanging bags. The astronauts slept standing up in the bags. They could not lie
flat in a normal bed, because they would float off.
The bathroom in skylab had a shower. So, the astronauts could wash
themselves. The shower was completely closed in. This was necessary to prevent
the water frome floating throughout the spaceship. Water and wastes had to be
pulled by pipes into storage containers.
The astronauts in skylab wore shoes that had special devices on
the bottoms. These devices linked with similar devices on the floor of the
spaceship. This kept the astronauts in one place as they worked or ate.
On the two earlier flights, astronauts had eaten from tubes(管) or
bags. They just squeezed(挤压) the
food into their mouths. On skylab, eating was a more normal activity.
The astronauts ate bread, meat, vegetables, and fruits. They
stored the food in freezers. They warmed it in special heating devices. Magnets
(磁铁) held down their knifes, forks, and
spoons. Covers kept the food from floating away. The astronauts drank water and
other liquids from p1ashc container similar to baby bottles.