The Olympic Games are held _____.
| A．for four years | B．each four year |
| C．every four years | D．every fourth year |
The level of the river ___ 20 centimeters over the security line and ____must be taken to control the flood.
| A．is measured; measures | B．measures; measurement |
| C．measures; measures | D．is measured; measurement |
Edison asked his father why the hens could hatch eggs ___he couldn’t.
| A．as | B．and | C．when | D．while |
The new suspension bridge ___by the end of last month.
| A．has been designed | B．had been designed | C．was designed | D．would be designed |
--How often do you attend the evening classes?
---_____, three times per week.
| A．On the whole | B．On average | C．Little by little | D．In all |
The sun was shining brightly, ____ everything there look more beau
tiful.
| A．making | B．to make | C．made | D．having made |