We walked in single file, and no one could see anyone else's face.
Everyone stood up and left the room in single file.
So we have to keep close together in single file.
The following shows how src2srcml and srcml2src can be used on single files.
Here they had to go in a single file, one at a time.
Single file the group went down the hall and out the back of the house.
All four of them put their left hands on the wall and started walking single file.
In single file they followed it for about half an hour.
I told him to line the troops up, single file.
Then I saw the family walking single file out of the house.