Correct the following sentences:

1. She said that she had finished the work long ago.

2. Peter said that those are his sweets.

3. The teacher told us that a square had four sides.

4. My best friend said that he would bought a gift for me.

1. She said that she had finished the work long ago. (no mistake of tense, better language would be - 'finished the work a while ago'.)

2. Peter said that those were his sweets.

3. The teacher told us that a square has four sides. (universal truth gets simple present tense)

4. My best friend said that he would buy a gift for me.