It appears to me that the translations of some of the sentences is a bit strange. For example, the translation for "他勉强被容许留在这里" is given as "He is here on sufferance." This sounds to me like the work of a Chinese person who is attempting to translate from a dictionary without understanding how we would actually express this idea as a native speaker of English. I'm only working on level 4 of the HSK, but wouldn't a better translation be "He is being forced to stay here"? I've noticed this same kind of strange English with other example sentences, too.

The example sentences are often a bit weird. If you see one that's whack, you can send a feedback from the practice page and we'll edit the sentence. Later we plan to get a much better set of example sentences in there and allow user editing and creation of example sentences.

Sorry, where do I see example sentences? I didn't notice them at all yet...
PS: I am studying Japanese. Maybe they aren't in there yet?

not for japanese unfortunately.

We plan to expand the example sentences to Japanese along with the other upgrades, but we're not working on it quite yet.