PREP You use of to combine two nouns, or a noun and a present participle, when the second noun or present participle defines or gives more information about the first noun. 用以连接2个名词或1个名词和1个现在分词，其中第2个名词或现在分词限定第1个名词或给出有关第1个名词的更多信息 [n PREP n/-ing]
the problem of having a national shortage of teachers.
一个全国性教师短缺问题。
having 在这里不是动名词吗？
如题
