In those days, our _________ concern was to provide people who were stopped by the snow storm with food and health care.

Please call Mary _______ 354—6403. A.in B. at C.to D. of

The children talked so loudly at dinner table that I had to struggle _________

Walmart, one of the largest supermarket chains, ________ some of its stores open 24 hours on Mondays through Saturdays.

下列各句中，加线词语使用恰当的一句是(　　)