幫我 check grammar.........

1)I have the opportunity of being a volunteer to sell flags for Tung Wah Group of Hospitals.
2)It is a challenging job for me because I have never sold flags before. **OK**
3)Fortunately,a middle-aged man bought the flags from me .
4)He has not recovered from his sadness. **OK**
5)I appreciate his bravery. **OK**

1)I have an opportunity to be a volunteer to sell flags for Tung Wah Group of Hospitals.
2)It is a challenging job for me because I have never sold flags before.
3)Fortunately,a middle-aged man bought the flags from me .
4)He had / have not recovered from his sadness.
5)I appreciate his bravery.