Mada mada desu

                             (translation: I still need to work hard.)

Ex.

      1. A : Wow, You made all these food?  You can be a chef, really!

          B : Thanks, but mada mada desu ( I still need to work hard. )  

　　　2.  A: What do you think of my drawings? Aren't they pretty good?

           B:Well, mada mada desu ne ( you still need to work hard on them.)