35. Being a parent is not always easy, and being the parent of a child with special needs often carries with ___ extra stress. 答案是it。很多解释上说it指代了being the parent of a child with special needs作为形式宾语存在。但是我不太明白it要是指代那个,那么句子的主语是什么。还有carry with是一个词组吗,还是说有其他的划分。求高手帮忙。