与此同时
Reach for this when you've described one event and want to introduce a second one happening in parallel — usually with an editorial undertone, like 'meanwhile.' It's a four-character transition phrase common in news, essays, and analytical writing. The two events are often contrasting or related in a way the speaker wants you to notice: while A is happening, B is also playing out. Written register; in casual speech 同时 alone is more natural.
Structure
[CLAUSE A]，与此同时，[CLAUSE B]
yǔ cǐ tóngshí
How to Think About It
Literally 'with this simultaneous' — 此 ('this') points back at what you just said, and 与此同时 launches the parallel development. Unlike English 'meanwhile,' it carries an analytical, news-anchor weight. If you use it in casual chat about your weekend, it sounds like you're narrating yourself on TV.
Examples
经济在快速增长，与此同时，污染问题也越来越严重。
Jīngjì zài kuàisù zēngzhǎng, yǔ cǐ tóngshí, wūrǎn wèntí yě yuèláiyuè yánzhòng.
The economy is growing fast; at the same time, pollution is becoming more and more serious.
他在国外学习，与此同时，他的父母在国内努力工作。
Tā zài guówài xuéxí, yǔ cǐ tóngshí, tā de fùmǔ zài guónèi nǔlì gōngzuò.
He's studying abroad; meanwhile, his parents are working hard back home.
新产品上市了，与此同时，公司也开始了大规模的广告活动。
Xīn chǎnpǐn shàngshì le, yǔ cǐ tóngshí, gōngsī yě kāishǐ le dà guīmó de guǎnggào huódòng.
The new product launched; at the same time, the company kicked off a large advertising campaign.
Common Mistake
Learners use it for plain co-occurrence — two unrelated things that just happen at the same time. 与此同时 wants the two events to be thematically linked, often pointing at a contrast or a bigger picture.
我在做饭，与此同时，我妹妹在睡觉。
公司的利润在上升，与此同时，员工的工资却在下降。
Don't Confuse With
同时
Plainer, works in speech and writing for any simultaneous action. Drop 与此 when you don't need the formal transition feel.
另一方面...
Sets up a deliberate 'on the other hand' contrast. 与此同时 is about timing, not viewpoint.
此外...
Adds a separate point ('in addition'). 与此同时 specifically frames things as happening at the same moment.
Practice
Fill in: 房价在上涨，____此同时，工资却没怎么涨。
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与
Fill in: 与此____时，全世界的人都在看这场比赛。
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同
Arrange: 与此同时 / 学习 / 我 / 工作 / ，/ 我 / 也 / 在 / 在
Show answer
我在工作，与此同时，我也在学习。
Translate to Chinese: Sales are increasing; meanwhile, costs are also rising.
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销售在增加，与此同时，成本也在上升。
Write one sentence using 与此同时 to link two parallel developments in a country or company.
Show answer
美国在加大对人工智能的投入，与此同时，中国也在快速跟进。
Hear It in Real Episodes
This pattern appears in 2 Fluentide episodes: