Complex sentence: At the beginning of the offensive the 7th Guards Army in a surprise night attack broke through defense of German 153th and 357th Infantry Division on the river Hron in a width of and within two days advanced about west to Nové Zámky.
Split into simpler sentences: At the beginning of the offensive the 7th Guards Army, in a surprise night attack, broke through defenses of German 153rd and 357th Infantry Divisions on the river Hron. The breakthrough had a width of and within two days the army had advanced about west to Nové Zámky.