When expressing something is about to happen, we could use 快/快要/要/就要……了 to indicate the state of an action.
快，要，快要 and 就要 are interchangeable in many cases. They all indicate something is just about to happen.
Subject + 快/要/快要/就要 + Adjective +了
天快/要/快要/就要黑了。(Tiān kuài/yào/kuàiyào/jiù yào hēile.) It’s getting dark soon.
雨太大，衣服快/要/快要/就要湿了。(Yǔ tài dà, yīfu kuài/yào/kuàiyào/jiù yào shīle.) The rain is too heavy, the clothes are about to get wet.
Subject + 快/要/快要/就要 + Verb (+Object) +了
我快/要/快要/就要搬家了。(Wǒ kuài/yào/kuàiyào/jiù yào bānjiā le.) I am going to move.
孩子快/要/快要/就要到学校了。(Háizi kuài/yào/kuàiyào/jiù yào dào xuéxiào le.) The child is almost at school.
快/要/快要/就要 + time words/quantifiers +了
“快” “要” can be followed by a particular point in time or a quantifier. In this case, it can be translated as “it’s almost…”.
快/要/快要/就要九点了，比赛马上开始。(Kuài/yào/kuàiyào/jiù yào jiǔ diǎn le, bǐsài mǎshàng kāishǐ.) It’s almost nine o’clock and the competition will start soon.
你吃得太多了吧，快/要/快要/就要五碗米饭了！(Nǐ chī de tài duō le ba, kuài/yào/kuàiyào/jiù yào wǔ wǎn mǐfàn le!) You have eaten too much, almost five bowls of rice!
1. Time （+ Subject）+ 就（要）+ Verb (+Object) + 了
With 就要……了, it could be used to indicate something would happen soon in a more specific time. 要 could be omitted here.
还有三分钟老板就(要)来了。(Hái yǒusān fēnzhōng lǎobǎn jiù yào láile.) The boss is coming in three minutes.
下个月就（要）考试了。(Xià gè yuè jiù yào kǎoshìle.) The exam is coming next month.
2. Subject + Time + 要 + Verb / Time + Subject + 要 + Verb
要could indicate the meaning of “be going to do something” or “planning to do something”, which could be used to talk about the future plan. In this case, the time word could be included.
这个工作没意思，明年我要换工作。(Zhège gōngzuò méiyìsi, míngnián wǒ yào huàn gōngzuò.) This job is boring. I will change jobs next year.
假期我要学游泳。(Jiàqī wǒ yào xué yóuyǒng.) I will learn to swim during the holidays.
我这个周末要去北京，你周末要做什么？(Wǒ zhège zhōumò yào qù Běijīng, nǐ zhōumò yào zuò shénme?) I am going to Beijing this weekend. What will you do this weekend?
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