A. to take B. when to take C. have taken D. being taken
A. putting up B. to be put up C. to pile up D. pile up
A. explaining B. explained C. to explain D. explain
A. To stay B. than stay C. than staying D. than have stayed
A. discovering B. having discovered C. to discover D. to have discovered
A. sell B. has sold C. be selling D. have sold
A. drinking B. to drink C. drink D. drunk
A. to change B. changing C. to be changed D. change