“As soon as . . . (then) . . .” = yī . . . ji - Cchatty

“As soon as . . . (then) . . .” = yī . . . jiù . . . 一 . . . 就 . . .

Yī 一 plus a verb, meaning “as soon as,” must always be followed by jiù 就:

As soon as he saw her, he (then) fell in love with her.
Tā yí kànjian tā, jiù àishang tā le.
他一看见她就爱上她了。

Note: jiù 就 in the second clause can NEVER be put in FRONT of a noun:

As soon as I return home, (then) I do my homework.

✔ CC: Yì huíjiā, wǒ jiù zuò gōngkè.
一回家，我就做功课。

✖ BC: Yì huíjiā, jiù wǒ zuò gōngkè.
一回家，就我做功课。