1 Who worked out the theory of radio receiving devices? 2 What did A. Popov invent? 3 How did the invention affect radio devices? 4 What are the main parameters of radio receivers? 5 Does sensitivity mean a measure of the receiver's ability to receive weak signals? 6 Which parameter means the ability of the receiver to reject undesirable signals? 7 What does fidelity mean? 8 The principle of operation of the radio receiver is not very difficult understand, is it? 9 Are there various types of receivers? 10 Where are used communication receivers? 11 Are broadcast receivers used in radio, telephone and telegraph service or in sound and visual programms?
I have got a sister, Kelly by name. I am 2 years older than my sister. Kelly and I are different. Her hair isn't as short as my hair. Kelly's nose is straight, and I've got a turned-up nose. My sister is a bit slimmer than I arm I think she is much more attractive than I because she looks like my mother, but I look like my father. He is very tall and I am the tallest in my class. Kelly likes wearing smart bright clithes. She is choosing a dress at the moment. I don't care much for clothes and bon't like bright things.
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