Sorry,I didn’t break the cup _______．I know it is your favorite，so I will buy you a new one．
| A．by mistake | B．ever since | C．on purpose | D．as usual |
Plants _________carbon dioxide and at the same time _________oxygen. So we may put some in our bedrooms to purify the air.
| A．take in, give out | B．take up, give off |
| C．take over, give in | D．take off, give up |
President Obama told television viewers that he saw ______ as his duty to run for a second term.
| A．one | B．that | C．this | D．it |
The girl carrying a dictionary, come in first, ______?
| A．doesn’t she | B．will she | C．will you | D．don’t they |
---Why do you pay a visit to your parents ________?
---_______ they live in a remote village far from here.
| A．occasionally; Because | B．every now and then; Since |
| C．from time to time; Now that | D．once in a while; As |
--- When shall we restart our business?
--- Not until we _____ our plan.
| A．will finish | B．are finishing | C．are to finish | D．have finished |