[不定项选择题]When does language acquisition begin according to the research?
A.It begins with the birth of a baby.
B.It begins before the birth of a baby.
C.It begins when a baby starts imitating adults’ speech.
D.It begins with a baby's cry melodies typical of its mother tongue.

[不定项选择题]共用题干 When We Are Asleep

Everyone dreams,but some people never recall their dreams,or do so very rarely.
Other people always wake up with vivid recollections（记忆）of their dreams, though they
forget them very quickly.In an average night of eight hours' sleep,an average adult will
dream for around one hundred minutes,probably having three to five dreams,each lasting
from ten to thirty minutes.
Scientists can detect when someone is having a dream by using an instrument which
measures the electrical waves in the brain.During dreaming,these waves move more
quickly.Breathing and pulse rate also increase,and there are rapid eye movements under
the lids，just as though the dreamer were really looking at moving objects.These signs of
dreaming have been detected in all mammals（哺乳动物）studied, including dogs,
monkeys, cats, and elephants, and also some birds and reptiles（爬行动物）.This period
of sleep is called the"D"state.Babies experience the"D"state for around 50%of their
sleep;the period reduces to around 25%by the age of 10.
Dreams take the form of stories,but they may be strange and with incidents not
connected,which make little sense.Dreams are seldom without people in them and they
are usually about people we know.One estimate says that two-thirds of the"cast"of our
dream dramas are friends and relations.Vision seems an essential part of dreams,except
for people blind from birth.Sound and touch are senses also often aroused,but smell and
taste are not frequently involved.In"normal"dreams,the dreamer may be taking part,or
be only an observer. But he or she cannot control what happens in the dream.
However,the dreamer does have control over one type of dream.This type of dream is
called a "lucid"（清醒的）dream. Not everyone is a lucid dreamer. Some people are
occasional lucid dreamers.Others can dream lucidly more or less all the time.In a lucid
dream,the dreamer knows that he is dreaming. In a lucid dream we can use Morse code to communicate with others.
A.Right
B.Wrong
C.Not mentioned

[不定项选择题]共用题干 Earthquake

How does an earthquake start?
What makes an earthquake happen? The rock of the earth's crust（地壳）may have a
"fault",a kind of break in the surface.The blocks which make up the earth move,and
sometimes this may cause the sides of the fault to move up and down or lengthways（纵向
地）against each other. When one piece of rock starts to rub on another with great force,a
lot of energy is used. This energy is changed into vibrations（振动）and it is these vibrations
that we feel as an earthquake.The vibrations can travel thousands of kilometers and so an
earthquake in Turkey may be felt in Greece.
What to do during an earthquake?
At school
As soon as the earthquake starts,students should get under the desks immediately and
wait until the teacher tells them it is safe to come out.The teacher should,at the same
time, go immediately to the teacher's desk, get underneath（在……下面）it and stay there
till the danger is over. Students must not argue with the teacher or question instructions.
As soon as the tremors（震动）stop, all students should walk towards the exit and go
straight to the school playground or any open space such as a square or a park.They must
wait there until the teacher tells them it is safe to go.
At home
If you are at home when the earthquake occurs,get immediately under the table in the
living room or kitchen.Choose the biggest and strongest table you can find.You must not
go anywhere near the window and don't go out onto the balcony（阳台）.Once the tremors
have stopped,you can come out from under the table but you must leave the building
straight away.You should walk down the stairs and should not use the lift一there may be a
power cut as a result of the earthquake and you could find yourself trapped inside the lift for
hours.
In the street
If you are in the street when the earthquake takes place,do not stand near buildings,
fences or walls一move away as quickly as possible and try to find a large open space to wait
in.Standing under trees could also be dangerous. The best way to leave the building during an earthquake is to get into a lift.
A.Right
B.Wrong
C.Not mentioned