Grammar: Choosing Conditionals for a Public Notice
A Class 12 student is finalising a four-line Japanese notice for a school recycling drive. The notice must be polite and fit on one A4 page. Two blanks need conditionals: 「このボタンを押す（ ）、警報が鳴ります。」 and 「質問がある（ ）、手を上げてください。」 The candidate may choose from と, たら, ば, and なら for each blank, but the same pattern need not be used twice. The candidate writes と in both blanks because と looks short and is easy to print. A classmate says と is fine because both sentences mean 'if'. The teacher says one blank is acceptable with と but the other is not, because と cannot introduce a request or invitation. The candidate has 20 minutes before the printer closes and must also keep the notice in です・ます体. The draft currently reads 「押すと、警報が鳴ります。」 and 「質問があると、手を上げてください。」
1. Which blank must change, and why? Give the replacement pattern.
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The second blank must change. 「質問があると、手を上げてください。」 is unnatural because the pattern と presents a natural consequence: if X happens, Y automatically follows. It cannot scope over a request, invitation, or volitional action such as 手を上げてください. The first blank is fine: 「このボタンを押すと、警報が鳴ります。」 describes an automatic mechanical result, which is the core function of と. Replace the second と with たら: 「質問があったら、手を上げてください。」 ば is also possible: 「質問があれば、手を上げてください。」
2. Explain why たら can replace と in both blanks while と cannot replace たら in the second blank.
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たら is a general conditional: it can mark a one-time event, a sequence, or a condition for a request, so it can cover both the mechanical result and the request. と is narrower: it marks a habitual or automatic consequence and normally cannot be followed by a request, invitation, or intention. That is why たら can replace と in both lines, but と cannot replace たら in the second line. The test is not 'do they both mean if?' but 'what kind of clause follows the conditional?'
3. Rewrite the two lines in polite notice style, keeping the meaning.
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Polite notice version: 「このボタンを押すと、警報が鳴ります。」「質問があったら、手を上げてください。」 The first line keeps と because the consequence is automatic. The second uses たら because the main clause is a request. Both remain in です・ます体 and fit the four-line limit.