Neil Coffey wrote:
There have been threads recently on how to devise a "native speaker" test. One of the points I have mentioned before is that one possible test is to test speakers' competence on points that are "on the fringe" of the grammar: cases that rarely come up in practice, but when they do, there is near consensus among native speakers.
One test could be recognising, for example, cases that require or are compatible with inversion vs cases that don't. In view of the foregoing, cases such as the following are interesting:
"Only a few miles away, [they found/did they find] the victim's body."
"Only once, [they found/did they find] the victim's body."
Sorry, just a random thought I wanted to share!
If identifying native speakers had been that easy, then that thread wouldn't have stretched to 150+ pages.
This is a simple grammar issue, which anyone who knows English (native or otherwise) will be able to spot at one glance as correct.