题目内容
If you go out sometimes at night, you'll see the moon high up in the sky. The moon is far away from the earth.
But it is our nearest neighbour in space. In 1969 two Americans visited it by spaceship. It was one of the most exciting moments of that year.
The sky looks black from the moon and you'll see the earth up in the sky. You will also see many, many stars.
You can't find any living things there. It's too hot in the day and too cold at night. And there's no air or water there. Nothing can live on it.
It is difficult for men to walk on the moon. Everything becomes much lighter. You can jump much higher on the moon than on the earth. If you throw a ball, it would fly very far. It's very interesting to walk on the moon!
(1) The story says you may ___________.
[ ]
A .throw the moon |
B .get to the earth |
C .get to the moon |
D .play balls on the earth |
(2) You'll see the earth _________ when you look up from the moon.
[ ]
A .on the ground |
B .in the sky |
C .in the rain |
D .in the snow |
(3) On the moon, a ball will ________ when you throw it.
[ ]
A .go very far |
B .not go very far |
C .fly to the earth |
D .look back |
(4) On the moon you can jump _________.
[ ]
A .just a little |
B .a metre high |
C .to the earth |
D .high |
(5) Does it rain on the moon?
[ ]
A .Yes. |
B .No |
C .Only on the grass |
D .Sometimes. |
The Indians invented and developed the system of numbers from 1 to 9 and 0. We can use the ten numbers to make any number from the biggest to the smallest.
However, the ancient Romans invented a different system (系统) of numbers. They used symbols (符号) and replaced them. 1 is “Ⅰ” and 2 is “Ⅱ”. For larger numbers, they invented new symbols—5 is “Ⅴ”, 10 is “Ⅹ”, and so on. But they didn’t have a symbol for zero.
Here’s a table of the Roman numbers.
1 | 5 | 10 | 50 | 100 | 500 | 1,000 |
Ⅰ | Ⅴ | Ⅹ | L | C | D | M |
The Romans combined their symbols. In this way, “Ⅶ” means “5+1+1”, or 7. However, they found that “ⅡⅡ” (for 4) and “ⅤⅡⅡ” (for 9) were too confusing, so they thought out another idea.
If the “Ⅰ” comes after the “Ⅴ”, then you add it (Ⅵ is 6); if the “Ⅰ” comes before the “Ⅴ”, then you subtract (减去) it (Ⅳ is 4). The rule is that you are allowed to add up to three (e.g. Ⅷ is 8), but only subtract one (e.g. XL is 40).
How to remember the symbols?
Ⅰis like a finger. In a whole hand, the thumb (拇指) and the little finger make a V. Ten fingers are both hands, so the two Vs make an X..
Here is a way to remember the other symbols (L, C, D, M):Little Cats Drink Milk.
( ) 51. How many numbers can we make according to the Indians’ system ?
A. three: 0, 9, 1 B. ten C. eleven D. lots of
( ) 52. Which number was not in the ancient Roman’s number system?
A. 1 B. 9 C. 0 D. 5
( ) 53. What does the underlined word “combined” probably mean in the passage?
A. 合并 B. 分离 C. 增加 D. 削减
( ) 54. What does MD mean according to the Romans’ rule of calculating?
A. 500 B. 1000 C. 1500 D. 2000
( ) 55 Which sentence is NOT true according to the passage?
A. “Little Cats Drink Milk” can help us to remember some of the numbers symbols.
B. The Indians invented the system of numbers from 1 to 9 and 0.
C. You are not allowed to make a number like “XXL”
D. The ancient Romans repeated symbols to make any number.