Вспомните правила образования и употребления пассивного залога

А. Найдите в тексте пять случаев употребления Passive Voice. Переведите предложения.

Б. Преобразуйте в следующих предложениях формы действительного залога в страдательный залог:

Пример: A transmission medium carries a signal.

A signal is carried by a transmission medium.

1. To understand how telecommuncations systems work we consider a number of essential concepts. 2. We use a prefix in metric units to designate some physical parameters such as length, speed and so on. 3. The table lists standard prefixes, their symbols, and their magnitudes. 4. A message is a physical manifestation of the information which the source produces. 5. We understand signals as electromagnetic waves that we use to transport the data over a physical medium. 6. A transmitter converts information to a signal. 7. A receiver then takes the signal from the channel and converts it into usable information. 8. Today modern telecommuncations not only use telegraphs and telephones but also exploit radio systems and fiber optics.