Each sentence has a mistake. Find it and correct it. 1)

Each sentence has a mistake. Find it and correct it.
1) Nobody told me how to behave on the interview. (a grammar mistake)
2) If you're good at drawing, you could be architect. (a grammar mistake)
3) It is the secretarys duty to answer the phone. ( a punctuation mistake)
4) She is respected for her efficiensy at work. ( a spelling mistake)
5) I prefer to work slowly. ( a spelling mistake)