The computer-simulated lady voice is saying "l'œuf". She adds the "l'" sound after "un". Just a bad simulation/recording. In the picture-matching exercise she adds a "b" sound before "œuf". Using a computer-generated machine voice is not an ideal way to hear a language. But hey, it's a free course; with limited funds they have done pretty well. But yes, I tend to gripe about the courses from time to time anyway.
Duo is extremely inconsistent when it comes to typos. Occasionally I'll miss an integral part of the sentence and have it be a typo, and sometimes i'll miss one letter of a word that could not be misconstrued and have it marked wrong.
Have a lingot to make up for it :(
I agree that the man's voice is much better than the woman's voice. When I use the French pronunciation app on google that voice is of much better quality than the lady's voice but of course as someone says it's free and I must admit I'm enjoying this course. I think it's super classy.
Because there are two present tenses in English. One it used for the "now" (I am eating currently/now) and the other for general truth (I eat eggs = I am not eating one now, but I generally eat them).
So the "to be + ing" present is closer in meaning to the French sentence here. By the way, Duo often accepts both tenses as a correct translation, but the countinous is more accurate in this case.