| 必须HSK 3 | bì xū | to have to; must; compulsory; necessarily | |
| 必要HSK 5 | bì yào | necessary; essential; indispensable; required | |
| 必然HSK 5 | bì rán | inevitable; certain; necessity | |
| 不必HSK 5 | bù bì | need not; does not have to; not necessarily | |
| 必将 | bì jiāng | inevitably |
| 1 | They must carry out the plan. | |
| 2 | Please turn off the power supply | |
| 3 | We must admit the fact. | |
| 4 | We must accept reality. | |
| 5 | Both parties must sign the contract. |