Why does your brother _______ a sad look on his face these days?

Many students don’t know how to _____ stress （压力）and become worried.— I think they can ask their teachers for help.

Do you know the boys on the beach—Sorry. It’s too far to see ______ clearly.

It’s 9 o’clock in the morning. It’s time .

Never before in China __________ so carefully concerned about the food safety.