Special attention should be _____ to air pollution wherever the factory will be built.

few years, the coal workers___________ their lungs X-rayed to ensure their health

The man we followed suddenly stopped ad looked as if________ whether he was going I the right direction.

Sorry， I didn’t hear you I to the music

33You can, __________ the sky is clear, see as far as the old temple on top of the mountain, but not today