I. Read the text and decide if the sentences are T (true) or F (false). 1. A mobile phone uses radio waves to communicate. 2. Mobile phones use three frequencies. 3. All base stations are clearly visible. 4. There is a base station in every cell. 5. Controllers can usually take all calls.

1. T — A mobile phone uses radio waves to communicate.
2. F — A mobile phone uses two frequencies: one for talking and one for listening.
3. F — Telephone companies sometimes disguise their base stations.
4. T — Each base station is at the centre of an area called a cell.
5. F — Controllers can take only a certain number of calls at the same time.

Ответ: 1 — T; 2 — F; 3 — F; 4 — T; 5 — F.