题目内容：

Complete the sentences by changing the active modals to passive modals.

That book (should return)________________tomorrow.

This letter (must send)__________________today.

This package (could send)______________tomorrow.

That package (should send)____________by express mail.

That box (can put away)_______________now.

These boxes (may throw away)_____________soon.

Those boxes(might pick up)________________this afternoon.

This room(will clean up)_____________________soon.

优质解答

should be returned
must be sent
could be sent
should be sent
can be put away
may be thrown away
might be picked up
will be cleaned up