【单选题】The meaning of ‘ebb tide’ is that ______.
A.
tide is falling from high water to low water
B.
tide is rising from low water to high water
C.
tide is reaching to a highest level
D.
tide is reaching to a lowest level
【多选题】离心式压缩机的优点有
B.
结构简单紧凑,运动件少,工作可靠,经久耐用,运行费用低;
C.
容易实现多级压缩和多种蒸发温度,容易实现中间冷却,使得耗功较低;
D.
离心机组中混入的润滑油极少,对换热器的传热效果影响较小,机组具有较高的效率。
【简答题】松解类按摩手法的基本要求可以概况为十个字:
【简答题】整复类按摩手法的基本要求可以概况为四个字:
【单选题】A tide is called diurnal when().
A.
only one high and one low water occur during a lunar day
B.
the high tide is higher and the low tide is lower than usual
C.
the high tide and low tide are exactly six hours apart
D.
two high tides occur during a lunar day
【判断题】往复式压缩机采用多级压缩和中间冷却,具有的优点是 往复式压缩机采用多级压缩和中间冷却,具有的优点是降低了排气温度,节省了功的消耗。