Task: Question Answering
Input (English): Context: Perhaps it came loose itself with use . I tightened it and got back to work . When I switched to my straight stitch machine , again I found the foot had been unscrewed and was loose . While I do occasionally need to switch feet on this machine , I had done no sewing the day before that would have forced me to unscrew the foot to switch it out . 
Question: How many machines do I have ?
Output (English): The one with the loose foot and the straight stich machine .