Change "Continue reading" into "Lees meer"

I am a newby in this.
But I did already spent hours and hours on what I thought is an easy thing.
i am making this website for my daughter using WordPress and the theme Clearstyle.
She asked me the simple question if I could change the words “Continue reading” in the dutch words “Lees meer”.

I think I have searched and replaced all the occurances of the “Continue reading” in all files but still the result is the same.

I will appreciate if someone can explain how I should be able to do that…

Thanks in advance,
Peter.