Rishe has kept a certain activity of hers secret from Arnold, but when he appears right in front of her, there's no escaping his notice. Later she learns that Michel believes Arnold fulfills every condition necessary to conduct a particular experiment.
It was just like breathing, 
or drinking water.
كان ذلك أشبه بالتنفُّس أو شرب الماء
Es war kaum anders
als zu atmen oder zu trinken.
Era como respirar o beber agua.
Era como respirar o beber agua.
C’était aussi naturel
que de respirer ou boire de l’eau.
Era come respirare o bere dell'acqua.
Era natural como
respirar e tomar água.
Сами по себе, как дыхание
или питьё воды.