听力原文： Tens of thousands of workers have been demonstrating on the streets of South Africa's largest city, Johannesburg as part of a national strike against unemployment and poverty. Workers carry banners demanding an end to privatization and action to devalue the currency, the Rand. The stoppage was called by the largest union grouping, the Congress of South African Trade Unions or COSATU. Our economics correspondent Andrew Walker says unemployment has been a long running problem in South Africa. 'Unemployment in South Africa is by any standard high. The most recent official figure for the jobless rate is around 26 percent of the work force. The recent strength of the South African currency, the Rand has made it harder for businesses to compete in foreign markets and against the imports at home But high unemployment has a long history. It was high under apartheid, partly reflecting the lack of education opportunities for black South Africans. Many analysts say it's still the ease that unemployment is due in part to job seekers not having the skills that companies need. But they say there has been progress.' The workers have been on a strike against ______.