Sustainable development is long-term ______which focuses on the environment and _____ natural resources．
| A．plan; preserve | B．plan; preserving |
| C．planning; preserving | D．planning ;preserve |
Information technology is taught in most schools，________ we have entered the information era.
| A．so | B．while |
| C．for | D．still |
It's really very dangerous.One more step，________ the baby will fall into the well.
| A．or | B．so | C．but | D．and |
There is still much to discuss；________，we shall return to this topic at the next meeting.
| A．yet | B．therefore |
| C．otherwise | D．however |
Knowledge is the food of thought ________，as long as it is put in our brain，we will grow wiser.
| A．but | B．when | C．then | D．and |
The number of the employees has grown from 1,000 to 1,200.This means it has risen ________ 20 percent.
| A．at | B．by | C．to | D．with |