Cái (Cn)

Situations

S1: Lan is talking to Thu about a friend (male) she has recently become acquainted with:

Anh ấy có ba cái nhà, một cái ở Đà Lạt, một cái ở Vũng Tàu và một cái ở Nha Trang.
(He has got three houses, one in Đà Lạt, one in Vũng Tàu and one in Nha Trang.)

In this situation, cái, classifying noun, used after a number, unitizes the mass noun referring to things. If the prior context defines the mass noun, then in subsequent uses the mass noun following cái can be omitted.

S2: Hearing that Tâm wants to buy a camera, Hải says:

Tôi thấy cửa hàng T. đang bán mấy cái máy ảnh rất hiện đại.
(I saw a few modern cameras in the T. shop.)

Cái usually appears after the quantifiers like mấy, vài, một số, nửa, etc., or after the articles like một, những, các.

S3: In the clothes shop, Lan pointed at a shirt and said to the owner:

[1] Cho em xem cái áo kia đi, chị.
(Show me that shirt, please.)
[2] Cái nào? Cái này cô mặc hợp lắm đấy.
(Which one? This one goes well with you.)

In [1] and [2], the classifying noun cái is used to unitize the noun phrases defined by the demonstratives like này, kia, or the interrogative nào.

S4: Lan's mother just came to the door when it started pouring. She called Lan:

[4] Lan ơi! Lấy cho mẹ cái áo mưa.
(Lan! Give me the raincoat.)

In this situation, it is not necessary for cái to be used with a number, quantifier or demonstrative like in S1, S2 and S3. The noun phrase cái áo mưa is understood when the listener (Lan) knows which one it is. In other words, the noun phrase cái áo mưa is singular and defined in the specific context.

S5: Hoa and Lan are talking about a film which has just been shown on TV:

[5] Cái hay của đạo diễn là để người xem tự tưởng tượng ra đoạn kết của bộ phim.
(The creative talent of the director was that he gave the viewers the chance to imagine the end of his film.)

Cái is used in this situation to nominalize a quality expressed by an adjective.

S6: Hải and Hùng are talking about their lives. Hải complains:

[6] Tôi còn rất vất vả. Phải lo cái ăn, cái mặc cho cả gia đình.
(I must still work very hard. I have to take care of food and clothes for my family.)

In this situation, cái is used to nominalize the verb, or in other words, to transform an action into a thing. Here, it is understood that cái ăn, cái mặc, etc. is something to eat or something to put on (food, clothing, etc.).

Definition

Cái, as a unit noun, is used before a mass noun to unitize the thing expressed by the mass noun which follows it. Cái is also used to nominalize a verb or an adjective.

  • Cái and chiếc, cây, bức, tờ, căn, etc.: In many cases, cái can be used in place of the other unit nouns such as chiếc, cây, bức, etc. especially in spoken Vietnamese. Ex.:
[1] Anh tôi cho tôi cây / cái bút này.
(My older brother gave me this pen.)
[2] Bức / cái bản đồ này chi tiết hơn bức / cái bản đồ kia.
(This map is more detailed than that map.)
[3] Chiếc / cái xe này tôi mua năm ngoái.
(I bought this motorbike last year.)

NOTE: Cái is only used in place of unit nouns referring to things (inanimate), but it is not used in place of con, a unit noun referring to animals (except for very small animals like cái sâu (a worm), cái kiến (an ant), etc.

On the other hand, cái cannot be used in place of classifying nouns referring to substances like viên gạch (a brick), cục đá (a stone), tờ giấy (a sheet of paper), giọt nước (a drop of water), tấm vải (a piece of cloth), etc. Cf:

[4a] Cục / *cái xà phòng này giá 6.000 đồng.
(This bar of soap costs six thousand dong.)
[4b] Anh chở đến nhà tôi 2.000 viên / *cái gạch.
(Take 2,000 bricks to my house.)
[4c] Anh có giấy không? Cho tôi một tờ / *cái.
(Do you have some paper? Give me one sheet.)

Combinations

  • cái + restrictive noun phrase Cf:
[1] Chiều nay tôi đi mua áo đầm.
(I am going to buy robes this afternoon.)

(We cannot say ... cái áo đầm)

[2] Tôi mua cái áo đầm ấy ở tiệm TiTi.
(I bought that robe at the TiTi shop.)

(We cannot say ... áo đầm ấy) The noun phrase áo đầm in [1] is the generic noun phrase that serves to indicate that this is not a shirt or áo dài, etc. That is why it does not require the presence of the classifying noun cái, while the phrase áo đầm ấy in [2] is a restrictive noun phrase that indicates a defined thing, therefore, it does require the classifying noun cái to precede it.

  • cái thì... cái thì... This construction is used to express a relationship of contrast between things of the same category. Ex.:
[3] Sáng nay tôi đã đi tìm mua vài cái quần jean, nhưng chẳng mua được cái nào cả. Cái thì quá rộng, cái thì quá hẹp.
(This morning I looked for some jeans to buy, but I did not get any. One was too big, the others were too small.)

Cf. thì (p. 361).