mountain和hill的區別：
mountain的意思是“山”、“山嶽”，其複數形式mountains 常表示 “山脈”，通常指比hill 大或陡峭的高山，例如：It’s the highest mountain in the world（它是世界上最高的山）。hill的意思是“小山”、“丘嶺”，通常指比 mountain 小的山，例如：The house stands on the top of the hill（房子位於山頂上）。
mountain柯林斯釋義
1、N-COUNT 山;山嶽;高山
A mountain is a very high area of land with steep sides.
2、QUANT 大量;大堆
If you talk about a mountain of something, or mountains of something, you are emphasizing that there is a large amount of it.
3、PHRASE 極大的困難;難辦的事情；棘手的難題
If you say that someone has a mountain to climb, you mean that it will be difficult for them to achieve what they want to achieve.
hill柯林斯釋義
1、N-COUNT; 小山;山岡;山丘
A hill is an area of land that is higher than the land that surrounds it.
We trudged up the hill to the stadium.
我們費力地爬到山上的體育場。
2、PHRASE 人老珠黃;在走下坡路;在衰退中;過氣
If you say that someone is over the hill, you are saying rudely that they are old and no longer fit, attractive, or capable of doing useful work.
