He knows it's almost impossible to finish the ,task he but he wants to have a try ______.

A Korean survey shows that shopping cart handles are the most bacteria-carrying items among some ________used objects.

---You know Mr. Green has been ill for days? ---Yes, I wonder if he is _________ better now.

It is well known to all that a machine needs fuel to run;    ,man needs food to live on.

—You don’t see the professor from Singapore quite often, do you? —No, we only meet ______．