Who did what?

Dare ga nani o shitanodesuka : who, what , did : Who did what ?

dare : who
nani : what
shita : did
desuka : ( "desuka" added at the end of the sentense make it interrogative.)
no : ( which connect a verb and "desuka". when connecting a noun and "desuka", no need to put "no")

eg.
hashiru : run
hashiru nodesuka : Do you run ?
hashitta : ran
hashitta nodesuka : Did you run?

pen : pen
pen desuka : Is this a pen?

Dare ga nani o shitanodesuka . : Who did what?
Dare ga nani o surunodesuka. : Who does what?
shita : did
suru : do

In the conversation, if you couldn' t catch some words, you can ask by substituting the word you caught for "who" or "what" in the above sentense.

Mr. Tanaka ga nani o shitanodesuka. : Mr. Tanaka did what?/ What Mr.Tnaka did?
Watashi wa nani o surunodesuka. : I do what? / What should I do?

It is very difficult to explain difference between " wa" and "ga" .Next time I will .