My computer ____start, no matter how hard I try.-lt might have crashed.

The research on the new flu virus vaccine ischallenging and demanding. Who do you think can do thejob— ____ my students have a try

He______on the farm for twenty years and now he is ateacher.

The audience________before TV sets are listening to Yi Zhongtian’s stories with their eyes________upon him[ ]

______ the day went on, we became closer and closer to each other[ ]