When she was doing the cleaning yesterday, Mum found the ring that she _____ years ago.
| A．loses | B．has lost |
| C．lost | D．had lost |
With all the books he was interested in ________， he left the library and went back to his dorm.
| A．borrowed | B．borrowing |
| C．to borrow | D．borrow |
They suggested that the professor ________ just now ________ chairman of the meeting.
| A．referring to；was made | B．referring to；be made |
| C．referred to；be made | D．referred to；was made |
—Can you introduce me a high quality machine?
—My pleasure. ________ well even on wet roads, this kind of car is very popular.
| A．Handled | B．To handle |
| C．Handling | D．Being handled |
The April Fools' tradition is said ________ in the sixteenth century.
| A．to start | B．to be starting |
| C．to be started | D．to have started |
It is said that sixty percent of all energy ________ in the world today is being lost as wasted heat.
| A．produced | B．producing |
| C．to produce | D．having produced |