1 in 1939
2 yes of course
3 
4 only few people owned TV in the next few years
5 Because of World War 2 
 because World War 2 had finished 
6 can be seen direct as everything occur .The boundaries of time and space have disappeared
7 is provided with help of a system of artificial  earth satellites 
8  a system using wires
9 in 1949 
 as a means of transmitting TV signals to rural and mountain areas far from big cities
10   black and white
11 it is a liquid- crystaldisplay
12 in a digital system usually continuous signal is replaced by a digital code containing detailed information on brightness. colour
13 continuous signal is replaced by a digital code 
14 look like minicomputer
15 put the programs you like into the memory
16 it is HDTV ot Hi vision
17 it is a  high definition television
18  Japanese manufacturers
19 plasma display
20 makes it possible to produce a large bright colour flat TV screen thin and light that it can also be hung on a wall like it framed picture