grammar problems

it is undeniable that adolescents encounter dozens of problems including pressure on studies.


including 之所以變左ing ,係因為:
先看original sentences原句=
*It is undeniable that adolescents encounter dozens of problems. Problems include pressure on studies. 是兩句簡單句子
Now use a relative pronoun以關係代詞 "which"連接 to combine the two sentences into one =
**It is undeniable that adolescents encounter dozens of problems which include pressure on studies.
*** use a present participle 用現在分詞取代 which + verb
= including to replace "which include" = 删去 which, 再將 include 變成 including 現在分詞
It is undeniable that adolescents encounter dozens of problems including pressure on studies.
including = present participle (not a gerund 這不是動名詞) = which include
*****以present participle 代 which + verb =高階修辭技巧的一種

Problems,(subject)
including pressure on studies,(Present participle,verbal adj.)
are for adolescents.(predicate).

不要想得這麼複雜，這個including其實本身是一個介詞(Preposition)，意思是包括，作用是帶出＂有甚麼在其中＂，如：

Cambridge dictionary online，就有兩例Eight people, including two children, were injured in the explosion. Including Christmas Day and Boxing Day, I've got a week off work

而牛津第六版也有兩例
Six people were killed in the riot, including a policeman.
I've got three days' holidays including New Year's Day.

希望幫到你！

2012-06-28 08:47:23 補充：
若你查考字典，就會發現including其實是介詞啊！