经过老师的解释，学生恍然大悟，原来如此简单。

Jīngguò lǎoshī de jiěshì, xuéshēng huǎngrándàwù, yuán lái rúcǐ jiǎndān.

After the teacher's explanation, the students suddenly realized that it was so simple.

在听了朋友的建议后，她恍然大悟，原来答案就在眼前。

Zài tīng le péngyǒu de jiànyì hòu, tā huǎngrándàwù, yuán lái dá'àn jiù zài yǎnqián.

After listening to her friend's advice, she suddenly realized that the answer was right in front of her.

在解决难题的过程中，他突然恍然大悟，找到了解决之道。

Zài jiějué nántí de guòchéng zhōng, tā tūrán huǎngrándàwù, zhǎodào le jiějué zhīdào.

In the process of solving a difficult problem, he suddenly had a moment of enlightenment and found the solution.