Chinese modal verbs appear before the verb to express the speaker's ability, possibility, or necessity. They are usually followed by a verb phrase to form a complete meaning. 能, 会, 要 are high-frequency modal verbs, each with a primary meaning.

Can indicates the ability or condition to do something, often referring to objective ability, physical condition, or external permission. It emphasizes the objective result of “can or cannot” rather than the skill itself.

Know-how indicates that one has learned a certain skill or knowledge, emphasizing mastery through learning. It is commonly placed before verbs for languages, talents, driving, and other skill-related verbs.

Will can also express future possibility, equivalent to English 'will' or 'is likely to'. It expresses a prediction and does not emphasize skill.

Be going to expresses subjective plans or intentions, similar to the English 'be going to'. It is commonly used to describe what the speaker plans to do next.

Be going to can express necessity or need, with a certain degree of obligation or objective requirement. This usage is common in advice, rules, or tasks.

Can emphasizes whether one has the ability or condition, while Will emphasizes whether one has learned the skill. For the same action, if you want to emphasize having learned it, use Will; if you want to emphasize whether it can be done, use Can.

Will expresses possible occurrence; Be Going To expresses intention to do something; The speaker uses 'Be Going To' to express plans or intentions, and 'Will' to express predictions.

Can, Will, and Be Going To are usually placed between the subject and the verb, forming the structure 'subject + modal verb + verb'. The verb may be followed by an object to form a complete sentence.

In spoken language, Can, Will, and Be Going To are commonly used to give brief answers, leaving out the following verb or complement. Such answers retain the original meaning.