The little boy is dirty from head to foot, because he _____in the mud all this morning.
| A．has played | B．is playing | C．has been playing | D．was playing |
In order to find out how the famous painting was stolen as soon as possible, more experienced policemen have been sent to _____ the case.
| A．look for | B．look up | C．look into | D．look through |
People today make choices of their diets______ what they believe.
| A．based on | B．basing on | C．are based on | D．being based on |
In our childhood, we were often ______ by Grandma to pay attention to our table manners.
| A．permitted | B．reminded | C．allowed | D．hoped |
I invited him to go to the cinema with me and he promised to. He didn’t,______.
| A．too | B．therefore | C．though | D．either |