Find the verb and give me its past form.
I think I should have eaten.
The verb in this sentence is "eat" and its past form is "ate".
Complete the following task based on the instruction and optional input provided.### Instruction:
Find the verb and give me its past form.

### Input:
I think I should have eaten.

### Output:
The verb in this sentence is "eat" and its past form is "ate".