"I am a weird woman."
Translation:أَنا امْرَأة غَريبة.
Why is there no short vowel mark under alif in the word for woman? Because it is not in the beginning of the sentence?
This kind of Alif is called (Hamzat Wassl: همزة وصل). You can think of it like a schwa and since the word before it is (Ana) it automatically cancels out as if the word for Woman starts with (M) instead of (A). If this word is to be starting the sentence, the (A) would be pronounced (rather short like a schwa as well). Bonus: When this word is defined, we do not write it as (الامرأة), this is wrong. But it is (المرأة) [al-mar'ah] - The woman.
I really dislike sentences that are useless to learn. For a beginner it is time wasted to learn something I have no need to say. Revise!
I'm not sure I agree -- if you want to develop a general facility with an unfamiliar language, I think it's important to encounter (and generate) utterances that might not be commonplace as long as they're grammatical. These help to keep the learner on their toes and pay attention (I know that I personally find these ones the hardest!). They also help to reinforce general patterns (here, i.e., the feminine ending on the adjective, of which we've only learned a handful at this point).
In my experience, Duo is useful for gradually and effectively building some basic versatility and familiarity, but if your goal is to pick up some useful conversational skills, relatively quickly, you might consider another platform (e.g. Pimsleur has learn-in-your car courses that I've found useful, and there's a lot of content on Youtube that focuses on phrases and expressions).