Usage note
及时用于描述做某事的时间恰当，不早也不晚。
jíshí yòng yú miáo huì zuò mǒu shì de shí jiān dāng qiē, bù zǎo yě bù wǎn。
及时 is used to describe when something is done at the right time, neither too early nor too late.
Context note
及时常用于提醒人们做事要把握时机，如及时回复邮件、及时完成作业等。
jíshí cháng yòng yú xǐng jì rén men zuò shì yào wā bǎ shí qī, rú jíshí huí fù yóu piàn、jíshí wán chéng zuò yè děng。
及时 is often used to remind people to act at the right time, such as replying to emails in a timely manner and completing homework on time.
5 examples
他及时回复了邮件。
tā jí shí huí fù le yóu jiàn。
He replied to the email in time.
妈妈提醒我及时完成作业。
mā ma tí xǐng wǒ jí shí wán chéng zuò yè。
Mom reminded me to complete my homework on time.
医生建议病人及时就医。
yī shēng jiàn yì bìng rén jí shí jiù yī。
The doctor advised the patient to seek medical attention in a timely manner.
我们得及时出发，以免迟到。
wǒ men dé jí shí chū fā， yǐ miǎn chí dào。
We must leave on time to avoid being late.
他没有及时支付账单，结果被罚款了。
tā méi yǒu jí shí zhī fù zhàng dān， jié guǒ bèi fá kuǎn le。
He didn't pay the bill in a timely manner and ended up getting fined.
5 mini stories
小明每天早上及时起床去上学。
xiǎo míng měi tiān zǎo shàng jí shí qǐ chuáng qù shàng xué。
Xiaoming gets up on time every morning to go to school.
妈妈提醒小红及时完成作业，以免考试不及格。
mā ma tí xǐng xiǎo hóng jí shí wán chéng zuò yè， yǐ miǎn kǎo shì bù jí gé。
Mom reminded Xiaohong to complete her homework on time to avoid failing the exam.
医生告诉病人要按时服药，才能及时控制病情。
yī shēng gào sù bìng rén yào àn shí fú yào， cái néng jí shí kòng zhì bìng qíng。
The doctor told the patient that taking medicine on schedule is necessary to control their condition in a timely manner.
小华没有及时完成作业，结果被老师批评了。
xiǎo huá méi yǒu jí shí wán chéng zuò yè， jié guǒ bèi lǎo shī pī píng le。
Xiaohua didn't complete his homework on time and was criticized by the teacher as a result.
妈妈提醒爸爸及时修理水管，以免漏水造成损失。
mā ma tí xǐng bà ba jí shí xiū lǐ shuǐ guǎn， yǐ miǎn lòu shuǐ zào chéng sǔn shī。
Mom reminded Dad to fix the water pipe in a timely manner to avoid leaks causing damage.
Mini dialogue
赶上校车
A
快一点，我们要及时赶上校车。
Kuài yīdiǎn, wǒmen yào jíshí gǎn shàng xiàochē.
Hurry up, we need to catch the school bus in time.
B
好的，我马上来！
Hǎo de, wǒ mǎshàng lái!
Okay, I'm coming right away!
谢谢帮助
A
谢谢你及时帮助我，不然我就摔倒了。
Xièxiè nǐ jíshí bāngzhù wǒ, bùrán wǒ jiù shuāidǎo le.
Thank you for helping me in time, otherwise I would have fallen.
B
不客气，下次小心一点。
Bù kèqì, xià cì xiǎoxīn yīdiǎn.
You're welcome, be careful next time.
Related words and contrasts
contrast
准时
zhǔnshí
on time
及时 means just in time to be useful; 准时 means exactly at the planned time.
related
立刻
lìkè
immediately
及时 suggests acting without delay to catch the right moment.