Overview
The ending (으)ㄹ 것이다 is a versatile grammatical construction used to express two primary concepts: future plans or intentions and suppositions or strong conjectures. While often introduced as a future tense marker, its role in expressing likelihood and inference is equally significant, making it more nuanced than a simple "will."
Usage
- Future Plans/Intentions: When attached to verbs, (으)ㄹ 것이다 indicates the speaker's future plan, intention, or a scheduled event. It's similar to "will" or "be going to" in English. It can also express a general future fact.
- Example: 저는 내일 도서관에 갈 것입니다. (I will go to the library tomorrow.)
- Supposition/Conjecture: This is a crucial function. When attached to verbs, adjectives, or the copula 이다, (으)ㄹ 것이다 expresses the speaker's strong guess, inference, or assumption about a current or past situation. It implies a high degree of probability based on evidence or common sense, often translating to "must be," "probably," or "it seems that."
- Example: 지금쯤 집에 도착했을 것이다. (He must have arrived home by now.)
- Example: 날씨가 추울 것이다. (It's probably cold.)
Conjugation Rules
The conjugation of (으)ㄹ 것이다 depends on the final sound of the verb or adjective stem:
- If the stem ends in a vowel or ㄹ (final consonant): Attach -ㄹ 것이다.
- Example: 가다 (to go) -> 갈 것이다
- Example: 만들다 (to make) -> 만들 것이다
- If the stem ends in a consonant (other than ㄹ): Attach -을 것이다.
- Example: 먹다 (to eat) -> 먹을 것이다
- Example: 좋다 (to be good) -> 좋을 것이다
- For the copula 이다:
- If the preceding noun ends in a vowel: -ㄹ 것이다 (학생이다 -> 학생일 것이다)
- If the preceding noun ends in a consonant: -일 것이다 (선생님이다 -> 선생님일 것이다)
Knowledge Plus
- Formal vs. Informal: (으)ㄹ 것이다 is a relatively formal expression. In casual speech, (으)ㄹ 거예요 or (으)ㄹ 게요 (for speaker's intention) are more common.
- Distinction from -겠-: While both can express future, -겠- often carries a stronger sense of speaker's will, intention, or ability, and can also express polite conjecture (e.g., 알겠습니다 - I understand/will understand). (으)ㄹ 것이다 is more about objective future events or a speaker's strong, evidence-based supposition.
- Past Conjecture: When combined with the past tense marker -았/었-, it forms -았/었을 것이다, indicating a strong supposition about a past event (e.g., 어제 비가 왔을 것이다 - It must have rained yesterday).
- Present Conjecture: When used with present tense verbs/adjectives, it expresses a present conjecture (e.g., 지금 자고 있을 것이다 - He must be sleeping now).