初二英语,,/

是because of her exciting 。
因为of是介词，介词后面要用名词，如果非得用动词，就要用动名词，所以用exciting，不用excited。excited是过去分词，不能充当名词。

because of her excitement.
1.这里需要名词
2.虽然exciting也可看作动名词的形式，但它有名词形式，所以这样最地道。

because of her excitment
exciting,excited 都是形容词，上面的错啦
because of 后面加名词excitment

because of++名词
her +++ excitement ==名词

那

...because of her exciting
of是介词 介词后面要用名词 后者动名词
所以...because of her exciting

because of her excitement