Translation of "Guarding" in Italian

Tom is guarding Mary.

Tom sta proteggendo Mary.

His role was to support Marshal Oudinot in  guarding the northern flank of the French salient.  

Il suo ruolo era quello di supportare il maresciallo Oudinot a guardia del fianco settentrionale del saliente francese.

And guarding the road to Paris. But by now he  was showing signs of exhaustion and disillusion.

e sorvegliando la strada per Parigi. Ma ormai mostrava segni di stanchezza e disillusione.