题目内容
（请给出正确答案）
A.n1＞n2
B.n1＜n2＞
C.n1=n2
D.n1=0
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A) if he didn't get a flat tire
B) if he had not had a flat tire
C) if the flat tire didn't happen
D) if the tire did not flatten
Every house gets its light either from daylight through the windows—which is the best to use—or from lamps or electricity;but whichever kind of light it is, the way it shines toward our book or work is a matter of great importance to the eyes.
Take a book，sit with your back toward the window，and try to read. Your shadow(影子)falls all over the page and makes it almost as bad for your eyes as if you were in a dark room.
Now turn around and face the window. The page is in the shadow again,while the bright light is in your eyes.
Try sitting with your right side toward the window. This is very well for reading, but if you were writing,the shadow of your hand would fall across the page and bother(打撹)you a little.
There is just one other way：sit with your left side to the window. Now everything is perfect for reading and for writing,too.
Whatever kind of light is in the room,the rule about the right to sit is always the same.
Which of the following is true？
A.How the light shines on our work is of much importance
B.The way the light shines on your work makes no difference
C.We needn’t care about where the light comes from
D.People can write or study under a light that comes from any direction
When you sit with your face towards the window,____.A.your shadow falls on your book
B.your book is in a shadow
C.the light is still dark
D.the light is on your page
The best way both for reading and for writing is to_____.A.sit facing the light
B.let the light shine from your back
C.sit with your right side towards the light
D.have the light come ffrom your left
Coal, oil, natural gas, and all other fuels are stored energy from the sun. Some was collected by this season's plants as carbon compounds. Some was stored by plants and trees ages ago. Even waterpower derives from the sun. Water turned into vapor by the sun falls as rain. It courses down the mountains and is converted to electric power. Light transmits only the energy that comes from the sun's outer layer, and much of this energy that is directed towards the earth never arrives. About nine tenths of it is absorbed by the atmosphere of the earth. In fact, the earth itself gets only one half millionth of the sun's entire output of radiant energy.
The sun is the source of all of the following EXCEPT______.
A．gasoline
B．natural gas
C．atomic power
D．animal fat
| Of these two basketball teams, the former comes from the US; the ____comes from England. |
[ ] |
| A. latter B. later C. late D. lately |
A、Accounts Receivable
B、Accounts Payable
C、Prepaid Accounts
D、Supplies Expense
| As a result of floods , huge quantities of good earth_______this year. |
[ ] |
| A. is washing away B. is being washed away C. one washing away D. are being washed away |
A、Three-level system
B、Four level system
C、Two level system
D、Five level system
B、N1 <n2>
C、N1=N2
D、N2=0
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