べき — Should / Ought To

By the end of this lesson, you will be able to use べき (beki) to express what someone should do or ought to do in Japanese. This is a strong, opinion-based expression of obligation or recommendation.

べき (beki) attaches to the plain (dictionary) form of a verb to mean "should" or "ought to." It expresses a personal or moral judgment about the right course of action. It is stronger than たほうがいい (tahou ga ii – "it's better to") and is common in N3-level speech and writing.

1. The Pattern

• Verb (dictionary form) + べき (だ/です)
• For する (suru – to do), the common form is すべき (subeki) rather than するべき.

2. Polite vs. Casual

• Casual: べきだ (beki da)
• Polite: べきです (beki desu)
• Past tense (regret): べきだった (beki datta) – "should have done"

3. Negative Form

• べきではない (beki dewa nai) – "should not"
• Polite: べきではありません (beki dewa arimasen)

❌ Using べき with ます-stem or て-form

• Wrong: 食べますべき (tabemasu beki)食
• Wrong: 食べてべき (tabete beki)食

✅ Always use the dictionary form

• Correct: 食べるべき (taberu beki)食
• Correct: すべき (subeki)

1. Fill in the blank with the correct form of べき:

   • 毎日運動___。 (Mainichi undou ___ – I should exercise every day.)毎日運動
   • Answer: するべきです (suru beki desu) or すべきです (subeki desu)
   毎日運動

2. Change to negative (should not):

   • タバコを吸うべきです。 (Tabako o suu beki desu. – You should smoke.)吸
   • Answer: タバコを吸うべきではありません。 (Tabako o suu beki dewa arimasen.)吸
   吸

3. Translate to Japanese:

   • "You should tell the truth."
   • Answer: 真実を言うべきです。 (Shinjitsu o iu beki desu.)真実言
   真実言

You now know how to use べき (beki) to express strong recommendations or obligations. Remember:

• Attach to the dictionary form of the verb.
• For する, use すべき (subeki).
• Negative is べきではない (beki dewa nai).
• Past tense is べきだった (beki datta) for regret.

Next step: Practice using べき in real situations—write 3 sentences about things you think people should do in daily life. Then learn how to soften advice with たほうがいい (tahou ga ii) for comparison.