Breakdown of densya ha hayakute benri desu.
Questions & Answers about densya ha hayakute benri desu.
What does the particle は do in 電車は速くて便利です?
Why is 速い changed to 速くて when connecting to 便利?
In Japanese, to link an i-adjective to another predicate (another adjective or verb), you turn the i-adjective into its て-form:
- Drop い from 速い → 速
- Add くて → 速くて
This て-form connection means “and,” so 速くて便利です = “is fast and (therefore) convenient.”
Why can’t we say 電車は速くです?
Because for predicates, an i-adjective uses its dictionary form plus です:
• Correct: 電車は速いです
The form 速くです would be the adverbial form plus です, which is ungrammatical in Japanese.
What kinds of adjectives are 速い and 便利, and how do they behave differently?
• 速い is an i-adjective (ends in い). Its て-form is 速くて. For a predicate you say 速いです or 速いだ (plain).
• 便利 is a na-adjective. When modifying a noun, you need 便利な本, but as a predicate you simply attach the copula: 便利です (or plain 便利だ).
Why don’t we say 便利なです or 便利な before です?
What is the function of です at the end of the sentence? Can it be omitted or changed?
です is the polite copula, giving the sentence a polite tone.
• In casual/plain Japanese you can replace it with だ: 電車は速くて便利だ。
• In very casual speech you might even drop the copula entirely: 電車は速くて便利。
Is it possible to reverse the order and say 電車は便利で速いです?
Could I split this into two sentences instead of using the て-form?
Yes. You can say:
• 電車は速いです。便利です。
But using the て-form (速くて便利です) is more concise and natural when you want to link two adjectives in one statement.
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