Breakdown of yídàn fāxiàn chónghài, jiù xiān kàn yèpiàn.
先xiān
first
就jiù
then
看kàn
to check
发现fāxiàn
to discover; notice
Questions & Answers about yídàn fāxiàn chónghài, jiù xiān kàn yèpiàn.
Why is 一 in 一旦 pronounced yí instead of yī?
This is because of the common tone-change rule for 一.
- 一 is normally first tone: yī
- But before a fourth-tone syllable, it usually changes to second tone
Since 旦 is dàn (4th tone), 一旦 is pronounced yídàn.
This kind of change is very common:
- 一天 → yìtiān (before 1st tone, it often becomes 4th tone)
- 一个 → yíge (before 4th tone)
So yídàn is the natural pronunciation.
What does 一旦...就... mean in this sentence?
一旦...就... is a common pattern meaning something like:
- once... then...
- as soon as... then...
- sometimes if ever... then...
In this sentence:
- 一旦发现虫害，就先看叶片。
it means:
- Once pest damage is discovered, first look at the leaves.
The pattern shows a condition followed by the action that should happen immediately or naturally after it.
Structure:
- 一旦 + condition/event
- 就 + result/action
So here:
- 一旦发现虫害 = once you discover pest damage
- 就先看叶片 = then first check the leaves
Why is 就 used here? Can the sentence work without it?