Historically, ________ main material for making tables has been wood, but ________ metal and stone have also been used.

Thesaleusuallytakesplaceoutsidethehouse,withthepeoplewatching________onbenches,chairsorboxes [ ]

are many kinds _____, but I don’tknow which to buy.

The computer system _____ suddenly while I was surfing the Internet.[ ]

You have ______ your family _______ a lot recently.