就要…了【jiùyào … le】

就要…了 says something is about to happen: 就要 goes before the verb and 了 closes the sentence. Unlike 快…了, it accepts a stated time.

With a time phrase

快…了 and 快要…了 refuse a time phrase. 就要…了 takes one, and 就 adds the sense that the date is sooner than you might think.

• × 他明天快走了 → 他明天就要走了

The time phrase goes before the subject or between the subject and 就要, never at the end.

• × 他就要走了明天 → 他明天就要走了

Without a time phrase, 就要…了 means the same as 快要…了, with a touch more urgency.

The final 了 belongs to the pattern. Without it, 他明天就要走 is a plain statement of plans, and the sense of something close at hand is gone.