为保持病室内空气清新,一般每天通风2次,每次的时间是()
A、10分钟
B、20分钟
C、30分钟
D、60分钟
E、90分钟

Life gets noisier every day and very few people can fre...

单项选择题Life gets noisier every day and very few people can free from noise of some sort or another.It doesn′t matter where you live--in the middle of a modem city,or a faraway village--the chances that you will be disturbed by jet aero planes,transistor radios,oil powered engines,etc.,are almost everywhere.We seem to be getting used to noise,too.Some people feel quite lonely without background music while they are working.
Scientific tests have shown that total silence can be very frightening experience for human beings.However,some people enjoy listening to pop music which is very loud,and this can do harm to their eardrums（耳鼓）.The noise level in some disco is far above the usual safety level for heavy industrial areas.
One recent report about noise and concentration（专心）suggested that although a lot of people say that any noise disturbs their concentration,what really affects their ability to concentrate is a change in the level of noise.It goes on to say that a background noise,which doesn′t change too much（music,for example）may even help people to concentrate.
Scientists have discovered that what prevents people from concentrating is

There are similarities between a journal research artic...

单项选择题There are similarities between a journal research article and a graduation paper. Which of the following statements is not correct:
A、They can focus on some unknown problems.
B、They are primary research.
C、They can be written by more than one researcher.
D、They can be written by university students.

Life gets noisier every day and very few people can fre...

单项选择题Life gets noisier every day and very few people can free from noise of some sort or another.It doesn′t matter where you live--in the middle of a modem city,or a faraway village--the chances that you will be disturbed by jet aero planes,transistor radios,oil powered engines,etc.,are almost everywhere.We seem to be getting used to noise,too.Some people feel quite lonely without background music while they are working.
Scientific tests have shown that total silence can be very frightening experience for human beings.However,some people enjoy listening to pop music which is very loud,and this can do harm to their eardrums（耳鼓）.The noise level in some disco is far above the usual safety level for heavy industrial areas.
One recent report about noise and concentration（专心）suggested that although a lot of people say that any noise disturbs their concentration,what really affects their ability to concentrate is a change in the level of noise.It goes on to say that a background noise,which doesn′t change too much（music,for example）may even help people to concentrate.
Some people may have their hearing hurt