1 . 根据句意，选择方框中的单词，用其正确的形式填入下列句子的空白处，每个单词只能使用一次。

ambition, ideal, decrease, proof, widespread, cooperate, overcome, cafeteria, suspect, involve

1. John Snow ________that the water pump was to blame.
2. The young man ________enormous difficulties and won the Olympic gold medal last year.
3. Chemical pesticides and artificial fertilisers have been in ________use in farming since the middle of the 20th century.
4. As well as studying hard, I’ve been ________in social activities.
5. People should ________the amount of fat they eat.
6. The ________diet is a balanced one, without too much or too little of any one thing.
7. In my youth my ________had been to be an inventor.
8. We should learn to ________with each other and make progress together.
9. Hot and cold food is available in the ________.
10. These results are a further ________of his outstanding ability.