Here are the sentences with corrections for the mistakes identified:

1. **Original:** Peter has told Mary to shut the door behind her but do not lock it.
**Corrected:** Peter has told Mary to shut the door behind her but not to lock it.

2. **Original:** After the meal, we played the games calling “What song is it?” and “Blindman’s bluff”.
**Corrected:** After the meal, we played the games called “What song is it?” and “Blindman’s bluff”.

3. **Original:** All Mike's friends fell sorry for him when he had to give up playing football.
**Corrected:** All Mike's friends felt sorry for him when he had to give up playing football.

4. **Original:** I think my sister is accustomed to work eight hours a day.
**Corrected:** I think my sister is accustomed to working eight hours a day.

5. **Original:** I tried to do everything to contact John two weeks ago but so far I don’t receive his reply.
**Corrected:** I tried to do everything to contact John two weeks ago but so far I haven’t received his reply.

6. **Original:** The letter was sent by special delivery must be very important.
**Corrected:** The letter that was sent by special delivery must be very important.

7. **Original:** There were such many people at the party that there wasn’t enough food for all of them.
**Corrected:** There were so many people at the party that there wasn’t enough food for all of them.

8. **Original:** Mai hardly never misses an opportunity to go out with her friends on the weekend.
**Corrected:** Mai hardly ever misses an opportunity to go out with her friends on the weekend.

9. **Original:** Don’t expect to learn all words in a day because learning language is time-consumed work.
**Corrected:** Don’t expect to learn all the words in a day because learning a language is time-consuming work.

10. **Original:** I sometimes wonder about my old friend, where is she now and what she is doing.
**Corrected:** I sometimes wonder about my old friend, where she is now and what she is doing.