Why do you suggest we buy a new machine?—Because the old one has been damaged ________.[ ]

This isn’t ______ pencil case. I left______ at home.

When the whole area was ______ by the flood，the government sent food and medicine there by helicopter.[ ]

four years’ research, we now have a ______better understanding of the disease.

When I woke up, I found myself ______ in bed and ______ by doctors and nurses.[ ]