People have come to understand _____ prevents so manyAmericans from being as happy as one might expect.

hoped to catch the 10：20 train, but _____ it wasgone.

More and more people in Shanghai choose to go to work__________ underground.

Eating more fruits and vegetables is good _________our health.

下列句中加横线词语发生活用的情况不同其它三项的是（ ）