We feel _____ our duty to make our country a better place.
| A．it | B．this | C．that | D．one |
I don’t think that rock music is terrible , ______?
| A．do I | B．don’t I | C．is it | D．isn’t it |
So little _____ with each other that the neighboring countries could not settle their differences.
A. they agreed B agreed they C. did they agree D. they did agree
Martin Cooper , a US researcher , was considered _______ the first cell phone .
| A．invented | B．to invent | C．having invented | D．to have invented |
He looked around and caught a man _____ his hand into the pocket of a passenger.
| A．put | B．to be putting | C．to put | D．putting |
They walked together as far as the second crossing ____ they parted .
| A．when | B．which | C．why | D．where |