The city has a heavy clay soil, so many residents opt for raised vegetable beds, says Ron Wolford, who works at the University of Illinois Extension.是什么意思_The city has a heavy clay soil, so many residents opt for raised vegetable beds, says Ron Wolford, who works at the University of Illinois Extension.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句