以下是从本单元课文中摘出的原句。试试看，能填上吗？要注意词形变化！

1．It was so narrow and small that we had to be careful to ________　________　________．

2．She once gave a magic book to Yu the Great and helped him ________ the flood ________　________．

3．For years it has been a strong attraction to me, but ________　________　________ I had never actually climbed it．

4．When we finally found ourselves under the highest layer of clouds, ________　________ we had glorious views of hills which had a kind of unimaginable beauty．

5．The Great Wall is different from ordinary city walls ________　________ it extends itself continuously for miles and doesn't encircle a city．

6．The Chinese name Changcheng or“Long Wall”________　________　________ because of its length．

7．According to records ________　________ in Chinese literature, as many as 20 principalities and dynasties took part in constructing the Great Wall．

以下是从本单元课文中摘出的原句。试试看，能填上吗？要注意词形变化！

1．Their subjects ________ running, climbing, swimming and flying．

2．She went on practicing running until her webbed feet ________ badly ________．

3．The rabbit was at the top of the class in running, but it ________ extremely ________ in swimming class．

4．In the climbing class he beat all the others to the top of the tree, but ________　________ using his own way to get there．

5．In most developed countries the government ________ free education ________ children because it realizes that ________ citizens are useful to the country in their later life．

6．Universities and colleges are places where some young people go to continue their education after ________　________．