【单选题】听力原文:W: Jim, thank goodness, you've arrived, the class presentation started half an hour ago and I was really desperate. M: I am terribly sorry that I'm late, Jane, This morning has been a real mess, ...
A.
Because there was a traffic jam.
B.
Because he got up late.
C.
Because his apartment is far away from the campus.
D.
Because he missed a bus and had to wait for another one.
【单选题】下图为液压千斤顶的工作原理图。P为压力,h为行程,A为活塞面积,则运动关系式为( )。
【单选题】下图为液压千斤顶的工作原理图。P为压力,W为负载,A为活塞面积,则( )。
【单选题】— Did your father come back early last night? — Yes. It was not yet eight o'clock ____ he arrived home. [ ]
【简答题】短语英汉对译 1)原始资料 2)observational research 3)探索性调研
【单选题】---- Did he come back early last night? ---- Yes. It was not yet eight o’clock _______ he arrived home.
【多选题】观察图1-2液压千斤顶工作原理图,设作用在小活塞上的力是F、作用在大活塞上的重物重量为G,小活塞和大活塞的作用面积分别是A 1 、A 2 ,小活塞与大活塞下腔的压力分别是P 1 、P 2 ,选出下面描述正确的选项( )