The fireman couldn’t __________ what the dark thing was through the heavy smoke．

40. You’ll have to_____ tickets early if you want to watch the football match.

I’m always ________ about what I say becausecareless remarks are likely to hurt others’ feelings.

His brother insisted on _______to have an English lesson _______ he didn’t feel well that day.

New technologies have made ________ easier to enjoy life than ever before.