A new technique ____ out, the yields (收成) increased by 20% .
| A．having working | B．having been working |
| C．has worked | D．had been worked |
82. When we heard the news that our team has won more than 30 gold medals Athena Olympic Games, we sang and danced _____ joy.
| A．to | B．with | C．at | D．Of |
81. In order to finish the work in time，they always worked far______ the night.
| A．in | B．onto | C．at | D．into |
80. Last week, we had a meeting. I told the chairman that I couldn’t attend it for I had something important to do, but he insisted _____ my being present.
| A．on | B．in | C．to | D．At |
79. I wrote to Mr. Green, _______ him _______ the lost case.
| A．inform…of | B．informing…of | C．informed…about | D．inform…for |
78. The form is very important. Please fill in the form _______ ink not _____ a pencil, Jack
| A．in; by | B．with; in | C．in; with | D．by; in |