Listening

Task 4 You will hear now part of a lecture about electric power transmission. As you listen, you will have to answer questions and complete a graph. There will be a pause after each section of the lecture to allow you to complete the tasks.

Section 1

1. What two factors are important in the transmission of power?
2. Look at the incomplete graph (Fig. 2).

· Write down the years 1890 to 1970 on the graph according to the information given.

· Write down the numbers 100 to 900 following the lecturer’s words.

· What do the numbers in the vertical axis represent?

Section 2

Completing the graph.

1. Draw the graph which the lecturer is explaining by placing dots (•) to indicate the maximum voltages transmitted in the years mentioned.

2. Connect the dots on the graph with solid lines to show the increase in maximum transmission voltage from 1890 to 1970.

Section 3

1. Are there any direct-current transmission systems in operation at the time the lecturer is talking about?

2. What is the main problem associated with direct-current transmission?

Дата добавления: 2015-08-03