conjecture

Astronomers conjecture that there might be a hidden planet at the edge of our solar system.

(Chinese) 天文学家推测，在太阳系边缘可能存在一颗隐藏的行星。

Without seeing the security footage, we can only conjecture about how the thief entered the building.

(Chinese) 在没看监控录像的情况下，我们只能臆测小偷是如何进入大楼的。

The theory that the virus was leaked from a lab remains pure conjecture without more data.

(Chinese) 在没有更多数据的情况下，关于病毒是从实验室泄漏的理论纯属猜想。

His historical claims are based more on personal conjecture than on archived documents.

(Chinese) 他的历史性主张更多是基于个人臆测，而非档案文件。