III. Answer the questions:

1. What is the purpose of tunnels?

2. Why is it a dangerous engineering work?

3. What are the ancient examples of tunnels?

4. What prejudices do tunnel crews have?

5. What do engineers start by?

6. What mistakes can be fatal?

IV. Choose the word from the list to complete a phrase: collapse, drown, crew, miner, survey, portals, wires, aligning

1. The_________begin the fight of their lives when the water pours into the tunnel.

2. A preliminary___________is carried out before construction begins.

3._________should be done several times.

4. But for the brave man passing by, a little boy, playing near the old bridge, might have

5. Bricks can be made hollow to allow_________ to be put inside.

6. Bridge is an example of a structure that_________after being in use for only 4 months.

7. The ends of a tunnel are also called the__________.

8. The___________worked hard to prevent an accident.

V. Study the words of Frequency and Measurement.

All buildings enclose space.

Buildings always/invariably enclose space.

Nearly all people live in houses.

People nearly always live in houses.

Most buildings have windows.

Buildings usually/generally have windows.

Many architects work in a design team.

Architects often/frequently work in a design team.

Some buildings have air-conditioning.

Buildings sometimes have air-conditioning.

A few people build their own houses.

People occasionally build their own houses.

Few people live in very cold climates.

People rarely/seldom live in very cold climates.

Very few buildings are portable. Buildings are very rarely/seldom portable.

No building lasts forever. Buildings never last forever.

VI. Use these words in the sentences. All/nearly all/most/many/some/a few/few/no

1. Architects have studied architecture at University.

2. Buildings have entrances on the ground floor.

3. Bridges are made of concrete.

4. People live in cities.

5. Blocks of flats are 50m high.

6. Architects are self-employed.

7. Buildings are erected on pile foundations.

8. Factories have solid walls.

9. Buildings are designed to keep out the weather.

10. Buildings are two-dimensional.

11. Channels are trapezoidal in cross-section.

12. People live near their place of work.

VII. Match the Problem of Tunnel Construction to its Solution.

1. An explosion of methane gas shook the tunnel.

2. Underground steam poured 70.000 gallons an hour into the tunnel.

3. They met faulted and broken shale and water at high pressure.

4. The flow of water increased to 300.000 gallons an hour, driving the crews out.

5. The water began to get hot and the temperature of the tunnel rose.

6. There was a possibility of water and sand breaking through the face of the tunnel.

a) They built heavy concrete bulkheads across the tunnel and pumped cement into the ground ahead.

b) The engineers decided to drive small tunnels, called drifts, on each side of the main tunnel to relieve water pressure.

c) They installed the enormous pumps and boosters with special coolers for the compressed air machines.

d) They used big tunnel pumps.

e) They went back and built a heavy concrete bulkhead to seal the tunnel.

f) They breached the bulkhead and dug on carefully, inch by inch, through the danger zone.