I have a doubt on my personal sentences.

Thank you.

By the way, is the sentence "her vocal cords will be operated on next week" correct?
What if I want to start the sentence with "she"?
I'm going through a bad time (I'm not going through a very good time is wrong?)

All the different ways to phrase these ideas are fine. You could also write, "She will undergo surgery on her vocal cords next week."

Great! I'd be happy to help you with your doubts about your personal sentences.

Regarding your first question, the sentence "her vocal cords will be operated on next week" is grammatically correct. It implies that someone else's vocal cords will undergo an operation next week.

If you want to start the sentence with "she," you can rephrase it as "She will have her vocal cords operated on next week." This emphasizes that it is she who will undergo the operation. Both versions are grammatically correct, so it depends on the emphasis you want to convey.

Regarding your second question, the sentence "I'm going through a bad time" is correct and commonly used. However, saying "I'm not going through a very good time" is also grammatically correct, but it sounds a bit awkward.

A more common way to express the same idea is to say "I'm not having a very good time." This phrasing is more natural and conveys the same meaning. Remember, expressing emotions is subjective, so both versions can be correct depending on the context and the speaker's intent.