or negation) and a holder (an experiencer of modality). Two examples of MN tagging are shown in Figure \[modality-example\].

[lp[5in]{}]{} (1)&[**Input:**]{} Americans should know that we can not hand over Dr. Khan to them.\
&[**Output:**]{} Americans `<`TrigRequire should`>` `<`TargRequire know`>` that we `<`TrigAble can`>` `<`TrigNegation not`>` `<`TargNOTAble hand`>` over Dr. Khan to them.\
\
(2)&[**Input:**]{} He managed to hold general elections in the year 2002, but he can not be ignorant of the fact that the world at large did not accept these elections.\
&[**Output:**]{} He `<`TrigSucceed managed`>` to `<`TargSucceed hold`>` general elections in the year 2002, but he `<`TrigAble can`>` `<`TrigNegation not`>` `<`TargNOTAble be`>` ignorant of the fact that the world at large did `<`TrigNegation not`>` `<`TrigBelief accept`>` these `<`TargNOTBelief elections`>`.

Note that modality and negation are unified into single MN tags (e.g., the “Able” modality tag is combined with “NOT” to form the “NOTAble” tag) and also that MN tags occur in pairs of triggers (e.g., TrigAble and TrigNegation) and targets (e.g., TargNOTAble).

We apply our modality and negation mechanism to the problem of Urdu-English machine translation using a technique that we call [*tree grafting*]{}. This technique incorporates syntactic labels and semantic annotations in a unified and coherent 