— I have got a headache.
— No wonder. You___________in front of that computer too long.
| A．work | B．are working | C．have been working | D．worked |
“You” _____ a very useful word in English.
| A．are | B．is | C．has | D．become |
_____ were nice to me when I was in the United States.
| A．The Brown’s | B．Brown’s | C．The Browns | D．Browns |
The population of city________ larger than that of any other city in the country.
| A．is | B．are | C．has | D．have |
Nothing except some chairs _____ there.
| A．was | B．were | C．has | D．had |
Many sheep _______ eating grass by the river.
| A．is | B．are | C．is being | D．have |