求问 一个语法知识点

simpquil

OG 语法15题
正确选项带回原句是
Many experts regarded the large increase in credit card borrowing in March not as a sign that housholds were pressed for cash and forced to borrow, but as a sign that households were confident they could safely handle new debt.
句中的 a sign that households were confident they could safely handle new debt.在 they could safely handle new debt前不应该加that么？如果不加那后面不是变成了run-on的形式了么？如果说是省略的话，曼哈顿里讲宾语从句里的that不是不能省略么？
求解释~谢谢~