Children in China today have nothing ______.
| A．to worry | B．worried | C．to worry about | D．worrying about |
A recent study has come up with _____ unexpected conclusion that ____ Africa elephants should be divided into two different species.
| A．a, the | B．an, the | C．an, an | D．the, the |
If I long enough to have a job, I would choose to be a doctor,those AIDS patients．
| A．had lived; helping | B．should live; help |
| C．were to live; helping | D．should have lived; help |
Once a difficult and even dangerous place , Vietnam is now a friendly detestation that welcomes visitors from all over the world .
| A．considered; visiting | B．considered; to visit |
| C．considering; visiting | D．considering; to visit |
There are no easy answers to questions brought to us by the rapidly changing world, we can try to turn challenges into opportunities．
| A．so | B．but | C．for | D．then |
If they what I was saying, they'd know what I was talking about
| A．took the trouble to listen to | B．had trouble listening to |
| C．take the trouble to listen to | D．have trouble listening to |