A、Every time they watch TV. B、When they make mistakes. C、When they’re going on holiday. D、When they meet forecasters. C原文提及“观众只在

In Britain, just after the main television news programmes, audience figures rise. It’s weather forecast time. The BBC broadcasts 44 live forecasts a day, 433 hours of weather a year, using forecasters from the Meteorological Office. The Met. Office makes predictions about the weather seven days in advance. These are based on observations from the ground, from satellites and from radar. The observations are stored in a computer that can do up to 4,000 million calculations a second.
    In Britain the weather is news. A television weather forecast often begins with an interesting fact— the town with the top temperature of the day or the place with the most rain. "The public like that kind of information," says senior forecaster Bill Giles. The BBC forecasters are professional meteorologists, but they do not have an easy job. They are the only presenters on television who do not use a script, and they cannot see the map that they are describing. Viewers are often critical, especially of female presenters. One woman left her job after rude letters and press reports about her clothes.
    The British talk about the weather more than almost any other subject, so it is a surprise to discover that seventy per cent of television viewers cannot remember what they saw on the weather forecasts. "What happens is that people like watching and hearing the forecasts, but they probably only take real notice when they need to—when they’re going on holiday or wondering what the weather will be like for the tennis at Wimbledon," says one forecaster. "Or, of course, when we make mistakes!
19. How many live forecasts does BBC broadcast each day?
20. What does a television weather forecast often begin with?
21. Why did the female presenter quit her job?
22. When will the viewers pay attention to the weather report?