在一天内完成这个项目是不可能的。

It's ___impossible to finish this project in one day.

这个谜题太难了，我觉得根本解不开。

The puzzle is so hard that it feels ___impossible to solve.

在这么短的时间内完成这项任务是不可能的。

It's ___impossible to finish this task in such a short time.