Being: 係 hai6

The verb 係 hai6 means 'to be' and is the Cantonese equivalent of Mandarin 是 shì. Every place you use 是 in Mandarin, you use 係 in Cantonese: 我係學生 ngo5 hai6 hok6 saang1 (I am a student) = Mandarin 我是學生.

The negative form is 唔係 m4 hai6 (is not), replacing Mandarin 不是 bù shì. For example: 佢唔係老師 keoi5 m4 hai6 lou5 si1 (He/she is not a teacher).

To ask 'is it...?' questions, Cantonese uses the 係唔係 hai6 m4 hai6 pattern (the A-not-A pattern), which is equivalent to Mandarin 是不是 shì bù shì. Example: 你係唔係香港人？ nei5 hai6 m4 hai6 hoeng1 gong2 jan4? (Are you from Hong Kong?)

Cantonese has a unique emphatic construction: 係...嚟嘅 hai6...lai4 ge3, meaning 'it IS...' with emphasis. This wraps around a noun or description to stress identity or classification. For example: 佢係醫生嚟嘅 keoi5 hai6 ji1 sang1 lai4 ge3 (He/she IS a doctor — emphasizing the fact). There is no direct Mandarin equivalent for this construction.

Note that, like Mandarin, Cantonese does NOT use 係 with adjectives. You say 佢好靚 keoi5 hou2 leng3 (she is pretty), NOT 佢係好靚. This is the same rule as Mandarin: 她很漂亮, not 她是很漂亮.