Question

you were driving very carefully for question tag

Answer 1

HEYA FOLK

QUESTION TAG IS WEREN'T YOU

EXPLANATION :

QUESTION TAG IN SIMPLE IS OPPOSITE TO  HELPING VERB   { NEGATIVE }

EXAMPLE : IF IT IS IS  IN STATEMENT ISN'T WILL BE QUESTION TAG

You were driving very carefully,WEREN'T YOU

Answer 2

the answer for the above question tag is as follows 

you were driving very carefully, weren't you