Be _____we can' t expect an absolute freedom of expression.

The twins are so much _______ that their parents can’t tell one from the other sometimes.

Calculations，which are astronomically exact，have been made ________ with the use of computers.

 Landing safely in bad weather is a _______ task for any pilot, and even the smallest error can lead to a disaster.

 Try to spend your time just on the things you find _______.