液压传动的两个工作特性是:压力决定于负载;速度决定于流量。

Ⅰ型呼吸衰竭的诊断，下列正确的是（）.

A.PaO₂>50mmHg，PaCO₂<50mmHg

B.PaO₂>60mmHg，PaCO₂>50mmHg

C.PaO₂>55mmHg，PaCO₂<30mmHg

D.PaO₂>60mmHg，PaCO₂<50mmHg

E.PaO₂<60mmHg，PaCO₂<40mmHg

People in many parts of the world are ______ for water, and more people will need more

water in the next century.[ ]

A. desperate

B. prime

C. user-friendly

D. explicit

Please make a list of ______ the celebration will need for the coming New Year and I’ll do the shopping.

A．what

B．which

C．when

D．where

压光机的作用？

计算题：在混凝土内埋设一支电阻温度计，温度常数α=5.29℃/Ω，最初测得电阻值R0=70.5Ω，三个月后测得电阻Rn=68.2Ω，试问该处的温度变化△T是多少？