Can "understand" be used either alone or with an objective? Cuz we say "I don't understand" quite often too!

Native speaker’s answer
Rebecca
You're right! You can use "understand" without an object. The very basic sentence form requires a subject and verb, but not always an object! You could even use the past tense form "understood" by itself without a subject. But the present tense form does require a subject. Ex: I understand. Ex: I understand what you're saying. Ex: Understood. => implying you understand what was previously said. A: What does Jane do for a living? B: She sings! => subject and verb