On the factory floor, protective hats and boots_______.
A: must be worn
B: must worn
C: must to be worn
A: must be worn
B: must worn
C: must to be worn
举一反三
- These piston rings are so badly worn that they must be （）.
- The letters on this gravestone have been _____ with time. A: worn on B: worn away C: worn out D: worn in
- We were completely ______ when we finally reached the destination. A: worn off B: worn down C: worn out D: worn away
- The<br/>ninety-minute match has( ) this player in his thirties, who is<br/>almost out of breath. A: worn away B: worn out C: worn on D: worn off
- ____, he still kept on working. A: In case he was worn out B: Even if he was worn out C: Though he was worn out D: Provided he was worn out