supposition|suppositions

这个理论建立在数据准确的假设之上。

This theory is based on the ___supposition that the data is accurate.

他的结论建立在未经证实的假设之上，缺乏可靠证据支持。

His conclusion was built on unfounded ___suppositions without solid evidence to back it up.

她的整个计划都是建立在所有人都愿意帮忙这一假设之上的。

Her whole plan was based on the ___supposition that everyone would be willing to help.