Ich bin nicht sicher, in welcher Sprache diese Frage zu beantworten ist, da sie teils auf Deutsch, teil auf Englisch gestellt wurde, was übrigens keine gute Idee ist. Es scheint darum zu gehen, wie sich bestimmte deutsche Sätze ins Englische übersetzten lassen. Obwohl die Frage in mehrfacher Hinsicht unklar ist, mache ich einen Versuch, einen wichtigen Punkt auf Englisch zu beantworten.
I am not sure in which language this question should be answered because it is asked in a mix of German and English, which is not a good idea by the way. It seems to be about how to translate certain German sentences into English. Although the question is unclear in more than one respect, I will make an attempt to answer an important point in English.
A problem that arises when trying to translate the last sentence is that the English modal verb can is a so-called defective verb insofar as there is no infinitive. There is no "to can".
In German, the equivalent verb können does have an infinitive, which is just können as mentioned before.
This means that there is no direct English translation for a sentence which uses the infinitive können. Fortunately, English offers an alternative: to be able to.
So the last sentence can be translated using to be able to which yields:
I will not be able to pass the test.