"He is not touching this blue egg."
Translation:הוא לא נוגע בביצה הכחולה הזאת.
I tested into this place and didn't learn in the notes that touch uses ב as its preposition. I suppose you just learn by getting it wrong the first time and seeing your mistake and getting it right later.
The difference is that זה is masculine while זאת is feminine. So since ביצה is feminine, in this sentence we would need to use "הזתא”
This is a complaint not only for this sentence but for all that ask you to click the words and put them in order––on desktop the words are displayed left to right, not right to left.