gate 2018 [closed]

Question

i completed 6 subject till now . (ds &c , daa,toc,cd,os,rdbms ) and

5 subject are remaining (co, dcld ,cn , discrete mathematics). but till now i am not doing privous year gate question of these subject ..

                                                                                                                                  
what will be the right dicision for me . doing remaing subject first or doing privous year gate question

i am confused what to do .

** can you please suggest me . some important topic of remaining subject like (co, dcld ,cn ,discrete mathematics ) which are more scoring. gate mostly ask from those topics .