tun
to do
To carry out an action or perform an activity. It is a very general verb for activity.
Was tust du gerade?
What are you doing right now?

to do
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to do
To carry out an action or perform an activity. It is a very general verb for activity.
Was tust du gerade?
What are you doing right now?

A typical mistake is to use 'tun' like the English 'to do'. For many activities, such as 'Sport machen' (to do sports/exercise) or 'Hausaufgaben machen' (to do homework), German has more specific verbs that are preferred.
Ich muss noch meine Hausaufgaben machen.
I still have to do my homework.
The use of 'tun' in the sense of 'legen' (to lay) or 'stellen' (to place/stand) is very colloquial. In formal or written texts, you should use more precise verbs instead, such as 'legen' (to lay), 'stellen' (to place/stand), or 'geben' (to give/put).
Kannst du bitte die Milch in den Kühlschrank tun?
Can you please put the milk in the fridge?
The expression 'mit etwas/jemandem zu tun haben' (to have to do with something/someone) is fixed. It is always used with the preposition 'mit' and the dative.
Ich will mit dieser Sache nichts zu tun haben.
I don't want to have anything to do with this matter.
The construction 'so tun, als ob ...' (to act as if ...) introduces a subordinate clause that describes what is only being pretended. The verb in this subordinate clause is often in Konjunktiv II.
Sie tut so, als ob sie alles wüsste.
She acts as if she knew everything.
In the expression 'es tut mir leid' (I'm sorry), the person who feels regret is always in the dative (mir, dir, ihm, ihr, uns, euch, ihnen).
Es tut uns sehr leid, dass wir den Termin absagen müssen.
We're very sorry that we have to cancel the appointment.
The verb 'weh tun' (to hurt) is also used with the dative to name the person who feels pain. The thing that hurts is the subject of the sentence.
Mein Rücken tut mir heute weh.
My back hurts today.
As with 'leid tun' (to be sorry) and 'weh tun' (to hurt), with 'gut tun' (to do good/be good for), the person who has the positive feeling is put in the dative.
Eine Tasse Tee wird dir guttun.
A cup of tea will do you good.
The expression 'es gibt viel zu tun' (there is a lot to do) or 'es ist viel zu tun' (there is a lot to be done) describes that work is pending. It is a common construction for expressing necessity.
Vor der Feier ist noch einiges zu tun.
There is still quite a bit to do before the celebration.
to give
'geben' and 'tun' can both refer to something coming to a place or to a person. 'geben' is used when someone hands something to another person or transfers it into their possession. 'tun' can colloquially mean that you put something somewhere. Learners may confuse the words because in some situations both can be used to talk about moving things. As a practical rule: with a person, you usually say 'geben'; with a place, in everyday language you often use 'tun', for example 'in die Tasche tun' (to put into the bag).

Morgen tue ich den Brief in den Briefkasten auf dem Weg zur Arbeit.
Tomorrow I’ll put the letter in the mailbox on my way to work.
Ich gebe dem Lehrer das Formular, bevor der Unterricht beginnt.
I give the teacher the form before class starts.