1 . Not everyone acts the same in response to events, and that is __________what triggers one person may or may not trigger another. (用适当的词填空)

2 . The reason I plan to go is _____ she will be disappointed if I don’t.（用适当的单词填空）

3 . Whether ways will be found to stop pollution or not is just _____ worries the public. （用适当的单词填空）

4 . The reason   ________we don't trust him is ________   he often lies. (用适当的词填空)

5 . From space, the earth looks blue. This is ________   about seventy­one percent of its surface is covered by water. (用适当的词填空)

6 . What has caused great confusion is ____________ the scientist made it without anyone else’s help. (用适当的词填空)

7 . You have made great progress in English. This is ________ you have improved your studying methods. (用适当的词填空)

8 . Although a number of tombs have survived with little damage,the truth is__________all have suffered at least some harm from centuries of rain,war,fire and theft. (用适当的词填空)

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

10 . At the end of the adventure, we had to choose to live in a cave. That’s_______________we could shelter from the snowstorm.(用适当的词填空)