"I see the strawberry."
Translation:אני רואה את התות.
In order to make the sentence sound complete and modern - the את is necessary. In older times it was less common and a sentence like אני רואה התות could sound regukar, but these days it sounds archaic and out of date, and for less professional ears, even a mistake. Because this is a modern Hebrew course - yes, the את is necessary. HtH