如图7所示,案秤是日常生活中常用来测质量的一种器材,如图7所示,其实它的实质是一个不 等臂杠杆,它的工作原理是_____________。称量时,若在秤盘下粘了块泥,称量的结果比实际质量_______;若秤砣磨损了,称量结果比实际质量___________。 答案:杠杆的平衡条件 大 大 People should be warned against using mobile
phones outdoors in stormy weather because they may “be struck by lightning”,
according to doctors.
Three experts have described how a teenage girl was struck by
lightning while using her phone in a large London park. The girl, aged 15,
recovered, but a year later, was still wheelchair-bound and found to be
suffering complex physical and emotional problems.
The girl also had a perforate eardrum(打孔耳膜)on the side where she
had been holding the mobile phone. She was having general recovery in Northwick
Park Hospital, Middlesex.Swinda Esprit, a senior house officer, said that
while the brain and muscle damage was similar to that of many lightning
victims—who can experience heart attacks on being struck— the ear problems were
not.
She said that the damages were particularly relevant for people
who might be involved in less serious lightning incidents, who might otherwise
recover, but would never get their full hearing back if struck while on the
phone.
“We were shocked by the damage, which is why we wanted to draw
attention to it,” Dr Esprit said. “A year on and she still was suffering these
difficult hearing.”
They added that three other cases had been reported in newspapers
in China, South Korea, and Malaysia. In the Malaysian case, a sales executive
was killed by lightning while talking on his phone during a thunderstorm near
Kuala Lumpur
“All these events resulted in death,” the doctors wrote.
“This rare phenomenon is a public health issue, and education is necessary to
stress the risk.”
The Australian Lightning Protection Standard recommends that
metallic objects, including cordless or mobile phones, should not be carried
outdoors during thunderstorms. However, “the United States National Weather
Service says on its website that both are safe to use “because there is no
direct path between you and the lightening”.
Paul Taylor, of “the Met Office”, said the ear injuries
were a consequence of mobile phones being metal, and not related to radio
waves.
Mr. Taylor said that mobile phones should be treated as another
piece of metal, similar to carrying coins or wearing rings, and people need to
be warned against the possible danger.
1.What do we know about the
teenage girl?
A. She was struck by lightning at
school.
B. She completely recovered from
being struck.
C. She still suffered from mental
problems.
D. She had to press her ear all day
2.It can be inferred that
damage done by lightening while using mobile phones ______.
A. is mainly in the brain and
muscle of the
victims
B. can be healed quickly except
for heart attacks
C. is less serious because the
victims can usually recover
D. is more serious than that when
one is not using a mobile phone
3. Why did doctors stress the
risk about using phones outside in lightening?
A. Because more people are faced
with it.
B. Because some deaths have been
caused.
C. Because lightning is harmful
for the brain.
D. Because a teenage girl
got killed.
4.We can infer from the last
three paragraphs that ______.
A. both cordless and mobile
phones are safe to use outside in lightning
B. there is no direct connection
between lightning and ear injuries at all
C. opinions differ as to whether
it is safe to use mobiles phones in lightning
D. ear injuries are the result of
carrying coins or wearing rings in lightning
5. The purpose in writing this
passage is ______.
A. to draw attention to the risk
of using mobile phones in lightening
B. to focus on various damages
done to lightning victims
C. to tell us the news that a
teenage girl was struck by lightning
D. to stress the danger of making
phone calls in lightning