I use an online dictionary and to look up some words.

I didn't understand, that's reason,eir meanings, which is why I want to use these words in a sentence.

You need to specify what you didn’t understand, unless it’s clear from context.

S…such as: to clear up, a bunch of, to be fed up.

This should be combined with the previous sentence.

-Your sister-in-law has never cleared up why she left her hausband.

-After three months, our problems hasve finally been cleared up.

“Problems” is plural.
“Have cleared up” makes more sense to me unless you want to specify who cleared up those problems.

After ona year, I have been cleared up to my uncle why I didn't come over to him ego visit my uncle in Freanche with him.

It sounds like “you” cleared up the situation yourself, so no passive voice.
“Come over” doesn’t make sense unless you are already there.

I always learn a bunch of words in EnglisEnglish words every day/week/month.

“Always” doesn’t really make sense with “a bunch of words” to me. This wording sounds better.

I didn't speak with them because they were talking without nonstop.

“Without stop” is not idiomatic. “Without end” would be fine but I think this is the word that you had in mind.

To be fed up.

“Fed up” is always used as an adjective.

I am just fed up tof clear upning the house after work.

She was fed up to stay alone without to meet somof being single and not meeting anyone in her life.

Finally, I want to thank everyone for helping and correcting me.