不自然な文章を直してくれませんか？


次の文は間違っていないが、不自然な文である。なぜ不自然かを説明してください。後は、文が自然になりうるコンテキストを考えてくれませんか？

> 先生がインフルエンザをうつしてくれたので、学校を休まなければならなかった。




This sentence is grammatically correct but semantically weird. This sentence
has [the subsidiary verb
くれる](http://www.guidetojapanese.org/favor.html#part3), which indicates the
teacher did something _good_ for you. In this case, you were negatively
affected by the teacher, so くれる is not an option. ~~so you should use the
passive form rather than くれる. This type of passive form is particularly
called["suffering passive"](https://japanese.stackexchange.com/a/1777/5010).~~
Here is the corrected version:

> 先生 **に** インフルエンザを **うつされた** ので、学校を休まなければならなかった。

(Note for more advanced learners: In fact, the sentence in question is not
absolutely incorrect because くれる is sometimes used when someone did something
bad for you. See [Using くれる for doing something
bad](https://japanese.stackexchange.com/q/938/5010) for details. This type of
くれる sounds arrogant and derogatory. Beginners should not use くれる in this
situation even when the teacher is not present.)

