液态烃分馏塔回流罐的压控管线连接的管网是()。
参考答案:高压瓦斯管网
Things are ________ on Mars ________ on Earth because of the different gravity.
A.much lighter; than that
B.much lighter; than those
C.not so light; as that
D.not so light; as those
按钮开关用于手动发出控制信号,以实现对各种运动的控制。