It has been frequently assumed, but not proved, that the majority of the migrants in what has come to be called the Great Migration came from rural areas and were motivated by two concurrent factors.

While the researchers assumed that the well-structured daily plans would be most effective when it came to the execution of tasks, they were wrong: the detailed daily plans demotivated students.

Here, it is assumed (and, indeed, it must be the case) that the file does exist.