参考答案:

1.It is uncommon to hear that a shipping company has made a calim for the cost of salvaging a sunken ship.
2.It is almost impossible to take your mind off the journey.
3.It is hard for energetic,quick-minded people to waste time,so they are often tempted to finish a job before setting out to keep an appointment.
4.It is impossible to look for life on another planet using earth-based telescopes.
5.It was difficult not to be tempted.