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

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

3 . One of his first findings was ___________articles in the science section were much more likely to make the list than non-science articles. (用适当的词填空)

4 . The second reason is _________people are living longer. A child born in the US today has a very realistic chance of living beyond 100 and needs to plan accordingly. (用适当的词填空)

5 . The truth is ___________we are lucky enough to have clean water whenever we want, but this is not the case for many people around the world. (用适当的词填空)

6 . My idea is __________you shouldn’t have left the country. (用适当的词填空)

7 . That is __________mice ruin many stores of grain every year. (用适当的词填空)

8 . What surprised us most is __________he spoke English so well. (用适当的词填空)

9 . The question, however，is this is ________ what the developing countries need the most. (用适当的词填空)

10 . College is ________ we should focus on a specific major, but high school is when we have to figure it out. (用适当的词填空)