It would be a good idea to use a plastic bottle, ___cut off, as a container to grow young plants in.
| A．of which the top | B．the top is | C．top of which | D．with its top |
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 |
The student corrected his paper carefully, _______ the professor's suggestions.
| A．follow | B．following | C．followed | D．being followed |