reduce decrease descend 区别

Descend指缓慢或渐进的移动,多是从斜坡下降.例如：mountain climbers descending from their overnight camp near the peak’s summit（从巅峰附近过夜的营地爬下的爬山者）;
decrease (名词亦为decrease,但重音在第一个音节上)强调数目或使人不快之物的逐渐减少.
如:to decrease the number of working hours,to
decrease traffic accidents.
The workmen want to decrease the number of working
hours and increase pay.
工人要求减少工作时间而增加工资.
reduce
可以表示尺寸、数量、程度或强度的减少,词义引伸之后,可以表示地位、处境、状况的降低.如:to reduce the speed,to reduce
household expense,to be reduced to tears,to be reduced to ashes.
This greatly reduced the speed of the ship ,for
there was danger that if she travelled too quickly,this rudder would be torn
away.
这大大减低了船速,因为如果它走得太快,这个舵会有被冲掉的危险.reduce 的名词为reduction,

reduce 这个是减少某某，比如：reduce risk
decrease 这个是某某减少，比如：risk decreases if 。。
descend 这个是指什么东西从空中下降，The plane descends.

Reduce是主观的减少，即其主语是reduce的执行者，举例如下：
She tried to reduce her weight.

Decrease是客观的减少，即主语是decrease的对象，举例如下：
Water consumption decreased during the winter.

而descend着重是下降、下倾、下斜等意...