Deciphering message word codes

Q : In certain code language 

1. 'pit dar na' means 'you are good'
2. 'dar tok pa' means 'good and bad'
3. 'tim na tok' means 'they are bad'

In that language, which word stands for 'THEY' ?

How to find the answers for this type of questions, these are the steps to be followed

1.  From sentence 1 & 2 the common word in English are GOOD.
2.  now check which coded word is same in both sentence DAR. 
3.  So the code for GOOD = DAR 

Similarly find the code word for BAD and ARE

 here BAD = TOK ( from sentence 2 & 3 ) 

ARE = NA  ( from sentence 1 & 3 ) 

Now that we have found the code for are and bad in sentence 3 the only word left is THEY  = TIM

hope this was useful