This is the 404th most frequent German word.
dadurch
"By that," "as a result," or "through that."
In this sentence, 'dadurch' introduces the consequence or result of the prior action specified.
Ich habe viel geübt, dadurch habe ich die Prüfung bestanden.
I practiced a lot, thus I passed the exam.
Here, 'dadurch' is used conjunctionally to explain the means or method that enabled the subsequent action.
Dadurch, dass er früh aufgestanden ist, konnte er den Zug pünktlich erreichen.
By getting up early, he was able to reach the train on time.
In this case, 'dadurch' references the cause or reason for her surprise.