1 to return / return / returned / returning
2 to close / close / closed / closing
3 to knock / knock / knocked / knocking
4 to attend / attend / attended / attending
5 to pick / pick / picked / picking
6 to remember / remember / remembered / remembering
7 to work / work / worked / working
8 to sit / sit / sat / sitting
9 to chat / chat / chatted / chatting
10 to wait / wait / waited / waiting