 Mkhedruli , in the 11th to 17th centuries also came to employ digraphs to the point that they were obligatory , requiring adhesion to a complex system . 
 Mkhedruli , in the 11th to 17th centuries also<a href='been_done' title='1'><mark></mark></a> came to employ digraphs to the point that they <a href='uninflect' title='2'><mark>were</mark></a> obligatory , requiring adhesion to a complex system . 
Mkhedruli , in the 11th to 17th centuries also done came to employ digraphs to the point that they was obligatory , requiring adhesion to a complex system .