The government __________ air quality in urban areas from level one to five ： excellent，fairly good, slightly polluted, poor and dangerous.
| A．arranges |
| B．classifies |
| C．distributes |
| D．divides |
As soon as he comes back, I’ll tell him when __________ and see him. \
| A．you will come | B．will you come | C．you come | D．do you come |
Our teacher said to us that the earth _________ around the sun.
| A．travelled | B．travels | C．is traveling | D．was traveling |
While _________, people sometimes can’t help buying something they don’t really need.
| A．shopped | B．being shopped | C．to shop | D．shopping |
Alexander tried to get his work ______ in the medical field.
| A．to recognize | B．recognizing | C．recognized | D．recognize |
You __________ buy a gift, but you can if you want to.
| A．must | B．mustn’t | C．have to | D．don’t have to |