Thanks.

> You can use \framed but like a minipage no page breaks are possible in a block.
>
> >/  This sets very well the german and the arabic text, with different interlinespaces. Is there a possibility to copy this into ConText?
> /
> You can use natural tables (or xtables) and use the loffset and roffset keys for
> margins between both columns. You can also hide the table commands in your
> own macros for the texts.

Maybe the minipages/frames are really the only possibility, so that I 
have to resign page-breaking, sad, but if this is the only way... 
Because without different line-interspaces the arabic text is definitely 
not well readable.

Now I tried it with frames; this is my try (from the wiki):

\starttext
\startcombination[2*1]
{\framed
    [width=4cm,
     align={flushleft}]
    {\input ward }}
{\framed
    [width=4cm,
     align={flushleft,nothyphenated,verytolerant}] % maybe also stretch
    {\tfb \input ward }}
\stopcombination
\stoptext

But it seems to not matter, if I write 2*1 or 1*2, in both cases the 
frames are set one below the other, and not side by side (what I want). Why?

Huseyin