It is the work of the internet.
More specifically an online translator.
We can usually tell for two reasons:
1) It contains examples of the imperfect subjunctive and was done after eight weeks of learning French.
2) It is absolute gibberish.
These students are, at best, cheating and, at worst, insulting our intelligence.
Very often it would have taken much less time to produce the work themselves rather than type it into an online translator and then copy it into their book.
Perhaps if they knew about Bad Translator they might be less inclined to let the internet do their homework.
After all, if online translators were perfect, most of us would be out of a job.
Bad Translator allows the user to enter any text up to 250 words. It then translates it back and forth up to 35 times into different languages and then back into English with, more often than not, hilarious results.
For example typing: