"You are as simple as a cat."
Translation:Bạn đơn giản như một con mèo.
Earlier in the group of 17 sentences, I got the Vietnamese Bạn đơn giản như con mèo. The accepted answer: You are as simple as a cat. I wondered why the Vietnamese sentence did not use một. Several sentences later, I come across the English sentence above. I repeat what DL gave me earlier: Bạn đơn giản như con mèo. And it is marked wrong. The inconsistencies in these lessons can be truly mind boggling.