下列各句中均有一处错误，请找出并改正。
1. Tom denied having seen these camera before.
2. His envy to his brother soon turned to jealousy.
3. The police accused him by stealing.
4. The young couple seated himself on a bench that stood by a lake.
5. How was that she managed to finish the work?
6. I promise whether you shall see him again before long.
7. Since it is such fine day, we might as well go home on foot.
8. As far as I know, their work is far from satisfaction.  

Key:
1. camera → cameras      2. to → of  
3. by → of                4. himself → themselves
5. was后加it               6. 去掉whether 或whether → that
7. such后加a              8. satisfaction → satisfactory