完形填空。 We can see walls everywhere in the world. But the Great Wall of China is 1 of all. The Chinese call it ' The Ten-Thousand-Li Great Wall'. It is 2 more than 6,000 kilometers long. It is 6-7 meters 3 and 4-5 metres from side to side. In most places, five horses or ten men can walk side 4 side along the top. When you visit the Great Wall, you can't help wondering how the Chinese people 5 build such a great wall thousands of years ago. 6 any modern machines, it was really very difficult to build it. They had to do all the work by hand. It 7 millions of men hundreds of years to build it. The Great Wall has a history 8 over two thousand years. The men began to built the first parts of it around two thousand seven hundred years 9 . Then Qin Shihuang had all the walls 10 . He thought that could keep the enemy out of the country. Today the Great Wall has become a place of interest. Both Chinese and people from all over the world come to visit it. (     )1. A. the big (     )2. A. in fact (     )3. A. tall (     )4. A. to (     )5. A. were able to (     )6. A. No (     )7. A. used (     )8. A. of (     )9. A. before (     )10. A. joined up B. biggest B. in the fact B. the all B. and B. be able to B. Not B. got B. on B. later B. join up C. the biggest C. in a fact C. higher C. by C. are able to C. Neither C. took C. for C. ago C. to join on D. the bigger D. on fact D. high D. or D. was able to D. Without D. spent D. about D. after D. to join of