【判断题】双级精馏塔可在上塔顶部和底部同时获得纯氮气和纯氧气。
【单选题】确定冠状动脉狭窄部位和严重程度的最佳检查是
【单选题】关于双级精馏塔获取纯氧和纯氮的说法正确的是( )
B.
双级精馏塔可在上塔顶部和底部同时获得纯氮气和纯氧气;
C.
双级精馏塔可以在冷凝蒸发器的蒸发侧取出液氮;
【单选题】At first, Australia was settled by the British as a colony
A.
to receive free settlers.
B.
to supply Britain with wool and food.
C.
to receive convicts from Britain.
D.
to expand the British imperial power.
【单选题】---I’m sorry I ______ my exercise book at home. ---Don’t forget _______ it to school tomorrow, please.