1£®The majority of people in the town are strongly in support of the plan to build a playground for children.

2£®It has been discovered that the traffic accident resulted from the driver's careless driving.

3£®The first thing he did was (to) finish(finish) his homework after school.

4£®We are planning to replace the old machines with/by some new ones.

5£®—Why does the lake smell terrible?

—Because large quantities of water have been polluted(pollute)£®

6£®The key to keeping(keep) this country a comfortable and clean place to live in is to control industrial pollution.

7£®The old scientist has made a breakthrough in growing rice£¬which will feed more people in the world.