阅读理解。
Modern inventions have speeded up people's lives amazingly. Motor-cars cover a hundred miles in
little more than an hour, aircraft cross the world inside a day, while computers operate at lightning speed.
Indeed, this love of speed seems never-ending. Every year motor-cars are produced which go even faster
and each new computer boasts (吹嘘) of saving precious seconds in handling tasks.
All this saves time, but at a price. When we lose or gain half a day in speeding across the world in an
airplane, our bodies tell us so. We get the uncomfortable feeling known as jet-lag; our bodies feel that they
have been left behind in another time zone. Again, spending too long at computer results in painful wrists
and fingers. Mobile phones also have their dangers, according to some scientists; too much use may
transmit
harmful radiation into our brains, a consequence we do not like to think about.
However, what do we do with the time we have saved? Certainly not relax, or so it seems. We are so
accustomed to constant activity that we find it difficult to sit and do nothing, or even just one thing at a time.
Perhaps the days are long gone when we might listen quietly to a story on the radio, letting imagination take
us into another world.
There was a time when some people's lives were devoted simply to the cultivation of the land or the care
of cattle. No multi-tasking there; their lives went on at a much gentler pace, and in a familiar pattern. There is
much that we might envy about a way of life like this. Yet before we do so, we must think of the hard tasks
our ancestors faced: they farmed with bare hands, often lived close to hunger, and had to fashion tools from
wood and stone. Modern machinery has freed people from that primitive existence.
1. The new products become more and more time-saving because _____.
A. the manufacturers boast a lot
B. time is limited
C. the prices are increasingly high
D. our love of speed seems never-ending
2. What does "the days" in Paragraph 3 refer to?
A. Simple life in the past.
B. Imaginary life.
C. Times of inventions.
D. Time for constant activity.
3. What is the author's attitude towards the modern technology?
A. Critical.
B. Optimistic.
C. Objective.
D. Negative.
4. What does the passage mainly discuss?
A. The present and past times.
B. Modern technology and its influence.
C. Imaginations and inventions.
D. Machinery and human beings.
2NH3。在10s内
的浓度由5mol／L降至4mol／L下列说法正确的是（ ）
表示的化学反应速率为0．1mol／(L·s)
的浓度或降低温度都会加快该反应的速率
、