1 . Fish­keeping is a widespread hobby and the keeper can ________ (观察) their behaviour in the glass tank and study its entire life cycle. (根据汉语提示单词拼写)

2 . Seeing the falling plane, painful memories of terrorist attack on Sept. 11, 2001 ______ (闪过) across his mind. (根据汉语提示单词拼写)

3 . We need to keep pushing the __________ (界限) instead of being satisfied with ourselves whenever we achieve a small step along the journey. (根据汉语提示单词拼写)

4 . Metals, plastic and cloth are all r________ materials which can greatly reduce the energy used to produce new ones. (根据首字母单词拼写)

5 . Human beings are taking advantage of r________ materials like paper and metals in order to reduce waste and save energy. (根据首字母单词拼写)

6 . R_________ in a family with 4 children, the eldest girl has learnt how to take care of her siblings because their parents were busy making ends meet. (根据首字母单词拼写)

7 . F__________ in 1945, the United Nations aims to promote peace and cooperation between the countries for the common good of human beings. (根据首字母单词拼写)

8 . L________ to the south of the equator, below many other countries on the globe, it's often informally referred to as down under（根据首字母单词拼写）

9 . In addition, studies show that c________ eating habits, for example, taking three meals a day at the same time each day, are better for our health. (根据首字母单词拼写)

10 . M______ by the Olympic motto “Faster, Higher, Stronger”, many well-known athletes have devoted themselves to achieving sporting excellence and pushing the boundaries of human achievement. (根据首字母单词拼写)