The expansion valve on a Freon system controls the （）. ["superheat of the gas leaving the compressor","back pressure in the evaporator","temperature of the icebox","superheat of the gas leaving the evaporator"]
燃料加入量少对烧结有什么影响？
Which is a negotiable document? （） ["Bill of Lading","Cargo Manifest","Export Declaration","Receiving Report"]
在三种不同风格的组合框中，用户不能输入数据的组合框是（） ["下拉式组合框","简单组合框","下拉式列表框"]
环境污染主要集中在：（） ["农村与工矿区","城市和农村","城市和工矿区","水源和土壤污染"]
燃料加入量多对烧结有什么影响？
