In Western countries, electricity, gas, and water are not luxuries but necessities. Companies now realize that consumers want products that will not only work effectively but also save money.

For most North American households, lighting accounts for 10 percent to 15 percent of the electricity bill. However, this amount can be reduced by replacing an ordinary 100-watt light bulb with an energy-saving bulb. These bulbs use a quarter of the electricity of standard bulbs and last eight times longer. Therefore consumers can save about US21 per bulb.

knew

didn't act

didn't waste-thought

spoke - would understand

would classify - thought 

were - wouldn't allow

Would you pick up 

would pass - were 

ate 

wouldn't travel

To cross the crowded streets is dangerous

Some frui juice has been bought 

Before I came home, my father had had dinner

Brown drives his car to work. 

Where does Tom come from?

What's wrong with this TV?

Are there 20 classes in Ha's school?

Ha has two elder sisters

He goes to school on foot everyday. 

it rained heavily, so the road in front of my house was flooded

We all had to wear goggles to protect our eyes. 

has lived

playing 

was built 

was bought 

inviting 

to play 

be done

took

playing 

crossing

A

Althogh the new restaurant looks good, it seems to have few customers.

Though it rained continously, we all enjoyed the trip

My brother usually plays the piano, and I usually play it as well