①As predicted by scientists,global pollution has become the most severe problem the humankind faces

②Competition for these positions is fierce——there are five times as many applicants this year as last year

③As the fact shows,educational programmes are supposed to accord with the national plan for economical development

④The car burns too much gas and the price is almost twice as much as I want to pay

⑤To know a vital international event,first of all,we need to think about its historical and polical background.