These round aluminum louvers, sometimes referred to as vents, can be inserted into round heating ducts and are perfect in situations where heat loss is a factor.是什么意思_These round aluminum louvers, sometimes referred to as vents, can be inserted into round heating ducts and are perfect in situations where heat loss is a factor.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句