1 . I was late for the appointment. That’s ______ I met an old friend on the way. (用适当的词填空)

2 . Perseverance is __________ it takes to do anything well. (用适当的词填空)

3 . Her confusion is ________ she should stick to her own way of life or follow the American way. (用适当的词填空)

4 . My question is ________ I can finish it in one hour. (用适当的词填空)

5 . Forty grams of meat per day is ________ people should consume in order to stay fit. (用适当的词填空)

6 . An opinion is ________ someone believes is true but has not been proved .

7 . A school-home is exactly ________ it sounds like. We get the homeless off the street, and we educate them so they don’t have to return to the street. We teach them how to be gardeners, painters, carpenters, bricklayers, electricians, and air-conditioning repairmen. (用适当的词填空)

8 . They lost their way in the forest and __________ made matters worse was __________ night began to fall.

9 . __________ Yang Liwei ate his food in space is __________ we want to know.