Formal:
* 我明白了 (wǒ míngbai le) - This is the most common and literal translation of "I understand". It is appropriate for formal situations.
* 我理解 (wǒ lǐjiě) - This means "I comprehend" or "I understand" and emphasizes the ability to grasp the meaning.
* 我懂了 (wǒ dǒng le) - Similar to "明白了", but slightly less formal.
Informal:
* 我知道了 (wǒ zhīdào le) - This means "I know" or "I understand" and is more casual than "明白了".
* 我明白了 (wǒ míngbai le) - This can also be used informally, though it is more commonly used formally.
Other options:
* 我知道 (wǒ zhīdào) - This is a shorter version of "我知道了" and is used in casual situations.
* 嗯 (én) - This is a simple affirmative response that can be used to indicate understanding.
The best way to say "I understand" in Chinese depends on the specific situation. Consider the context and your relationship with the person you are speaking to.