（1）主动的、一般的动作
特点：
1）此时若将现在分词改成定语从句，则定语从句的谓语要用一般时态。
2）此时现在分词多数表示的是所修饰名词的一种持久性的特点，并不是强调正在发生的动作。
a.Unidentified Flying Objects (UFO) = unidentified objects that fly
不明飞行物
b.flying fishes = fishes that can fly 飞鱼
c.a promising young man = a young man who promises well
有前途的年轻人
d.the exploiting class = the class that exploits others　剥削阶级
e.an understanding man = a man who can understand others' feelings
善解人意的人
f.a puzzling problem = a problem that puzzles people　令人迷惑的问题
g.They live in a room facing the south. = They live in a room that faces the south.　他们住在一间朝南的屋子里。
（2）主动的、正在进行的动作
特点：
1）此时若将现在分词改成定语从句，则定语从句的谓语要用进行时态。
2）此时现在分词多数表示的是所修饰名词的一种短暂性的特点，强调正在发生的一个动作。
a.falling leaves = leaves that are falling 　正在飘落的叶子
b.The man standing at the gate is my English teacher. = The man who is standing at the gate is my English teacher.
c.I like the girl dancing with that guy. = I like the girl who is dancing with that guy.
d.the setting/rising sun = the sun that is setting/rising
e.the barking dog = the dog that is barking
f.a sleeping child = a child who is sleeping