The average Facebook user in the United States has 245 friends，according to a study ______in February.
| A．publishing |
| B．published |
| C．publish |
| D．to publish |
The library's study room is full of students _______ for the exam.
| A．busily prepared | B．busy preparing | C．busyly prepare | D．are busily preparing |
The scientists were waiting to see the problem _______.
| A．settle | B．settled | C．to settle | D．settling |
The foreigner tried his best, but he still couldn't make his point _______ .
| A．understand | B．understanding | C．to understand | D．understood |
People _______ in the city do not know the pleasure of country life.
| A．live | B．to live | C．lived | D．living |
The _______ price will save you one dollar for each dozen.
| A．reduce | B．reducing | C．reduced | D．reduces |