那个青少年深深皱着眉头，显然对情况感到沮丧。

The teenager frowned ___deeply, clearly ___frustrated with the situation.

他因为解不出这道数学题而感到很沮丧。

He felt ___frustrated because he couldn't solve the math problem.

连续三次面试失败让他感到非常沮丧。

Failing three job interviews in a row made him feel extremely ___frustrated.