奉命的英语

The Dog in the Manger出自《伊索寓言》(Aesop's Fables)，

The Dog in the Manger is a fable attributed to Aesop, concerning a dog who one afternoon lay down to sleep in the manger. On being awoken, he ferociously kept the cattle in the farm from eating the hay on which he chose to sleep, even though he was unable to eat it himself, leading an ox to mutter the moral of the fable:

People often begrudge others what they cannot enjoy themselves.

狗站马槽的故事，说的是一头狗躺在堆满稻草的马槽里，狗是不吃草的动物，而当马或牛一走进稻草时，这头狗却朝着马，牛狂哮，不准食草动物享用。

因此，“狗站马槽”就成了一个家喻户晓的成语而进入英语中，常用来比喻a person who prevents others from enjoying sth that is useless to himself; a churlish fellow who will neither use a thing himself nor let others use it，讽刺那些占据说职位或某些物质却不做事的人。

首先，没有定式这一说；不定时就是to do sth;

授之以鱼，不如授之以渔

其他的in on at等等的区别可以去百度词典上去找更准确的答案，要我回答，我也是去那儿复制的，找到后认真看，重在理解，用心记。

像语法可以去英语学习网，那里有更人性化的教学~~~

努力学习，祝你考个好成绩！