Classify the following sentences into "past tense" and "present tense".
- I saw a movie
- I am watching a movie
- Past tense: "I saw a movie"
- Present tense: "I am watching a movie"
Complete the following task based on the instruction and optional input provided.### Instruction:
Classify the following sentences into "past tense" and "present tense".

### Input:
- I saw a movie
- I am watching a movie

### Output:
- Past tense: "I saw a movie"
- Present tense: "I am watching a movie"