A demonstrable fact or quality can be shown to be true or to exist.
例句
The road safety programme is having a demonstrable effect on road users...道路安全方案在道路使用者身上逐渐显现出明显的效果。Despite its demonstrable speed and safety, the boat failed to become popular.虽然其速度和安全性都可得到证明,但这种船还是不受欢迎。