Whats the difference between ... 你刷牙吗? nǐ shuǎ yá ma？ 刷牙了吗? shuā yá le ma? Do they both mean 'have you brushed your teeth?' Thank you. The direct translation for the first one is 'Do you want to brush teeth?' and the second one is 'Have you brushed your teeth?'. The 了 implies something in the past. You may want to check out words like 了, 已經, 要, 會. (The words are in traditional Chinese, not simplified Chinese. Please convert them into simplified ones using Google sorry for that.) They carry a past or future meaning.

你刷牙吗? means ' Do you want to brush your teeth?' 刷牙了吗？means 'Did you brushed your teeth?' It's past tense I hope can help you.

你刷牙吗？ has a meaning of " do you want to brush teeth now" present or future Sorry, my English level is limited. Hoping it can help you. :)

Do they both mean 'have you brushed your teeth? No, they don't. Just this one "刷牙了吗?" is the meaning that have you brushed your teeth? In my opinion, this sentence, 你刷牙吗? means you're asking someone about his hygiene habit. When you ask me the question, 你刷牙吗, I will answer you, "Of course, I always brush my teeth!" That's what the difference is.

你刷牙吗? nǐ shuǎ yá ma？ ----- Do you brush your teeth (regularly) ? / Do you want to brush your teeth now? / Would you brush your teeth (in a certain period of past time)? / Will you brush your teeth( in a period of future time)? ● Chinese has no systematic marks (tenses) for verbs (and adjectives, part of which can work as a predicate without an element like that in English: verb be or other linking verbs) to apparently indicate the time of the action or condition/attribute, and in oral conversation Chinese often does not display the time with words, such as 今天，去年，现在( or rather omits it because you know it from the context, as in any other language); therefor in conversation, a sentence can be of multi-meaning, though the listener is clearly aware of its exact meaning from the context. 刷牙了吗? shuā yá le ma? ---------- Have (had) you brushed your teeth?