Let's leave this issue as it is for now.

Let's leave it as it is.

Let's finish this project once.

Let's accept his proposal for one time.

Once the rain stops, let's go for a picnic.

Can you answer this question?

No problem, I will do that job.

That proposal is completely unthinkable.

As a practical question, how are we going to fund this project?

This exam is a matter of life or death for me.