When should we use the word 'ONLY' in our sentences?

Are these sentences correct?

1. ONLY I hit him in the eye yesterday.
2. I ONLY hit him in the eye yesterday.
3. I hit ONLY him in the eye yesterday.
4. I hit him ONLY in the eye yesterday.
5. I hit him in ONLY the eye yesterday.
6. I hit him in the ONLY eye yesterday.
7. I hit him in the eye ONLY yesterday.
8. I hit him in the eye yesterday ONLY.

The answer:
All of those sentences are correct.  Each one of them carries a different meaning as per below;

1. ONLY I hit him in the eye yesterday. (No one else did.)
2. I ONLY hit him in the eye yesterday. (Did not slap him.)
3. I hit ONLY him in the eye yesterday. (I did not hit others.)
4. I hit him ONLY in the eye yesterday. (I did not hit outside the eye.)
5. I hit him in ONLY the eye yesterday. (Not other organs.)
6. I hit him in the ONLY eye yesterday. (He doesn’t have another eye.)
7. I hit him in the eye ONLY yesterday. (Not today.)
8. I hit him in the eye yesterday ONLY. (Did not wait for today.)

Using "12 A.M." and "12 P.M." is actually WRONG! (Common Error in English)

The time should be stated as 12 noon and 12 midnight. The letters “a.m.” stand for ante meridiem, a Latin phrase which means “before noon” and the letters “p.m” stand for post meridiem, which means “after noon”.
To say 12.00a.m or 12.00p.m at noon would therefore be wrong, since noon cannot be before or after itself. As for midnight, is it before or after noon? It would be safer and clearer to call it 12:00 midnight.