继而: and then, as the next step
【高55】连词 / conjunctions
Tone colorsā tone 1á tone 2ǎ tone 3à tone 4a neutral
继而 links a fact A to the next step B, which follows from it: in a chain of effects, or in a change of mind. It opens the second clause, whose subject is usually not repeated: 持续降雨使河水上涨，继而造成低洼路段积水 (the rain makes the river rise, which then floods the low streets). You can translate it as "and then, as the next step" or "which in turn leads to".
It is used to tell how one thing leads to another: 患者先是发烧，继而出现咳嗽; 他起初不同意，可继而一想，又觉得是个好机会. It is a written word, common in the press and in reports.
Do not mix it up with 然后 / 接着 (neutral, they are enough for a mere sequence of actions: 我吃了早饭，然后去上班), with 于是 (hsk3-g29), which links a cause to the reaction or decision it triggers, or with 进而 (hsk6-g01), which marks a deliberate advance to a broader or deeper stage.
Examples
患者先是发烧，继而出现咳嗽和呼吸困难。
Huànzhě xiānshì fāshāo, jìér chūxiàn késou hé hūxī kùnnán.The patient first ran a fever and then developed a cough and difficulty breathing.
价格上涨影响了市民的消费，继而影响了整个行业。
Jiàgé shàngzhǎng yǐngxiǎng le shìmín de xiāofèi, jìér yǐngxiǎng le zhěnggè hángyè.The price rise hit residents' spending and, in turn, the whole industry.
暴雨冲垮了山路，继而切断了村里的电力供应。
Bàoyǔ chōngkuǎ le shānlù, jìér qiēduàn le cūnlǐ de diànlì gōngyìng.The storm washed out the mountain road and then cut off the village's power supply.
媒体先报道了这件事，继而引发了公众的广泛讨论。
Méitǐ xiān bàodào le zhè jiàn shì, jìér yǐnfā le gōngzhòng de guǎngfàn tǎolùn.The media reported the matter first, which then sparked wide public discussion.
他起初并不同意，可继而一想，又觉得这是个好机会。
Tā qǐchū bìng bù tóngyì, kě jìér yì xiǎng, yòu juéde zhè shì ge hǎo jīhuì.At first he did not agree, but on second thought he felt it was a good opportunity.
Common mistakes
✗ 我吃了早饭，继而去上班了。 → ✓ 我吃了早饭，然后去上班了。 (a mere sequence of actions is not a chain of effects: 然后).
✗ 他累了，继而睡了。 → ✓ 他累了，于是睡了。 (a cause and the decision it prompts: 于是, hsk3-g29).