Your classmate is packing up to leave the library without finishing their assignment. You need to tell them, firmly, that the deadline is today and there is no flexibility. In Mandarin, that kind of strong obligation uses 必须 (bìxū), an HSK 3 grammar pattern that means "must" with zero room for negotiation.
Place 必须 right before a verb to say someone must do something. It is much stronger than 应该 (yīnggāi, "should") and signals that there is genuinely no choice. The key example from this lesson:
你必须今天交作业。
nǐ bìxū jīntiān jiāo zuòyè
"You must hand in the homework today."
Here 必须 sits directly before 交 (jiāo, "to hand in"), making the obligation absolute. You can use the same structure to remind a friend to bring their passport, tell yourself you must wake up early, or explain a rule that cannot be broken.
This is a live conversation lesson — you talk out loud with AI teacher Mei Lin in real time, by voice, not typing. Over roughly 10 minutes, Mei Lin gives you situations that call for 必须 and listens as you respond. She corrects your grammar and pronunciation in the flow of conversation and adapts to your level, so the practice feels natural rather than mechanical.
By the end, you can tell someone what they absolutely must do — whether it is meeting a deadline, following a rule, or taking care of their health — and make it clear there is no room for debate.
When you're ready, explore more HSK 3 lessons or try "Setting Easy Conditions" (只要...就) and "Not Even One" (一 + MW + 也/都 + 不/没) — two more live lessons at the same level. You can also print free handwriting worksheets for HSK 1–3 vocabulary to reinforce what you learn.
必须 (bìxū) means "must" and is placed right before a verb to express strong obligation with no choice. It is much stronger than 应该 (yīnggāi, "should"). In the "Saying You Must" lesson, you practice it with sentences like 你必须今天交作业 (nǐ bìxū jīntiān jiāo zuòyè) — "You must hand in the homework today."
Instead of watching an explanation, you talk out loud with AI teacher Mei Lin in real time by voice. She gives you scenarios that require 必须, you respond, and she corrects your grammar and pronunciation as you go — adapting to your level throughout the roughly 10-minute conversation.
Yes — the first live conversation lesson is free, and no credit card is required to start talking. Each lesson targets one grammar pattern and takes about 10 minutes, so you can experience the format without any commitment.
SayMei offers live lessons for many HSK 3 patterns, including "Setting Easy Conditions" (只要...就, zhǐyào...jiù) and "Not Even One" (一 + MW + 也/都 + 不/没). You can browse all available options on the HSK 3 lessons hub page once you finish working on 必须.