What or that?

Yes, it is a mistake to say: All what I have done…. What cannot be used as a relative pronoun coming after a noun or pronoun. We have to use the relative pronoun that and say: All that I have done…. Or, if that is the object of the relative clause as in this example, we can simply omit it, use zero pronoun instead and say: All I've done…

• All (that) I've done is to offer to help him with his homework. I haven't done his homework for him.

Here are some more examples. Note that that cannot be omitted if it is the subject of the relative clause as in the last example below:

• Everything (that) you ordered is now in the shop and can be collected.
• The paintings (that) I bought are now hanging on the walls in my house.
• The only thing that keeps me awake at night is wondering if the house is properly insured.
  

What can, however, be used to introduce a clause where it combines the function of noun and relative pronoun and means that which or the thing(s) that:

• What I did was help him with his homework, not do it for him.
• What he does in his free time doesn't interest me.
• I don't remember what time he went to bedlast night. (what = the time at which)
• I have no idea about what happened after I left.
  

Noun-verb collocations

In your example, Maria, of students gave their feedback on certain arguments, the verb which best collocates with arguments here is raised, so the sentence would read:

• The students gave their feedback on the arguments raised by their teacher.

Collocation (or co-location if you like) refers to the way in which some words regularly occur together. We do not usually treat arguments. We normally would not say that. Instead, we raise arguments or discuss arguments.

However, if we are talking about wounds or injuries, these are the things we treat. We might also treat a topic or subject if we are writing an essay as an alternative to dealing with it.

• His injuries were serious and could only properly be treated in hospital.
  
  
• How do you propose to treat this topic when you are writing about Napoleon?

In language learning, it's very important to develop an understanding of words that regularly occur together. Test your knowledge of these noun-verb collocations in the text below. One of the alternatives listed is the best fit or the normal collocation. Choose that one.

• The female crocodile usually assembles/builds/manufactures/erects her nest on the banks of a river. She normally lays/releases/drops/spawns about fifty eggs.
  She then closes/shuts down/seals/binds the nest for protection against predators. Provided the nests are not molested/assaulted/bothered/disturbed, the baby crocodiles proceed/hatch/appear/arise from the eggs after about twelve weeks.

Now scroll down the page to check your selections

Crocodiles, birds and insects all build their nests.
They lay their eggs.
And crocodiles seal their nests for protection against predators.
If they are unlucky, their nests might be disturbed by predators. But if they are lucky, the baby crocodiles will hatch from the eggs after twelve weeks.