公企鹅本能地等待，他自己也不确知为何这么作，只是本能叫他这么作。

This male penguin waits instinctively; not really knowing why, other than instinct tells him to do it.

youdao

在我的书桌里有好几封写就了好久的信，到今天还没有发出去，因为我不确知地址有否错误。

I have some letters in my desk that have been written for weeks, but there was some slight uncertainty about the address or the contents, so they are yet unmailed.

youdao

我不确知未来，但我相信通过艰苦的工作加上一点点的运气和朋友们的帮助，我一定能够心想事成！

I do not know for certain what the future holds but I am confident that with hard work, a little bit of luck and a supportive network of friends, I can be as successful as I want to be.

youdao