完成这个项目是一项艰巨的任务。

Completing the project was a ___formidable task.

当面对艰巨的任务时，她常常感到气馁。

When confronted with ___formidable tasks, she often feels disheartened.

克服如此巨大的障碍需要极大的决心。

Overcoming such a ___formidable obstacle requires immense determination.