题目内容：

    Television is one of the greatest technological inventions of the twentieth century. A Scottish man called John Logie Baird invented it. Inventors in the USA and Europe were working on electronic television systems (系统) but Baird used a mechanical (机械的) system. In 1925, he was able to send the first black and white picture — of the head of a doll — from one end of his flat (公寓) to the other. He then used a local office boy, not the doll, and this teenager was the first person ever to appear on TV. Baird made the first television programmes for the BBC in 1929. These programmes had sound, not just pictures.

However, Baird’s system was very limited and basic. A totally electronic system was more popular and practical (实用的). The inventor of this electronic system was an American, Philo Farnsworth. In 1936, the BBC started using Farnsworth’s system because the picture was better than Baird’s.

Colour TV began in the USA in the 1940s but only a small number of people had colour televisions in their houses. They were very expensive. In Britain and the USA, the first regular (有规律的) colour TV programmes only began in 1967.

Now in the 21st century, we have digital (数字的) television. TV has changed a lot since the face of a boy appeared on TV in John Logie Baird’s flat!

1.Is television a great technological invention of the 20th century?（根据短文内容回答问题）

2.When did Baird make the first television programmes with sounds?（根据短文内容回答问题）

3.Who invented the totally electronic system? （根据短文内容回答问题）

4.从短文中找出与下列句子划线部分意思相近的短语或单词。

In 1936, the BBC started using Farnsworth’s system. _____________________

5.In this passage, the underlined（划线） word “they” refers to（指的是）____________