您想表达的应该是 我经常因这对双胞胎长得很相像而将她们弄混淆
句子中用到短语 be confused with 与 ... 混淆
此句子应改为 I am confused with the twins because they looked alike.（with each other可省）
confused此时作定语,为形容词
拓展,另外,记得与
“be confused with 与 ... 混淆” 区分的一个短语是 “ be confused about 对 ... 感到困惑”
望采纳哦,亲~~