We can use the -ing form of the verb: 动名词可以有几种用法
1.as a noun: 作为名词, 例如 the time for sleeping
-ing nouns are nearly always uncount nouns 一般动名词作名词用时属于不可数名词
作为名词时,可以作为主语：
Learning English is not easy.
也可以作为动词后的对象
We enjoy learning English.
也可以作为介词后的对象
Some people are not interested in learning English.
2.as an adjective: 同时也可以作为形容词,例如你的sleeping problems的用法
放在名词前,做定语：
Do you have some sleeping problems?
放在名词后,做状语：
Who is that man standing over there?
3.其他的就应该是作为动词的现在分词来用,一般跟在be动词后面
I am reading an English novel.