故 (gù) — therefore; hence; so

Character

Strokes: 9
Radical: 攵 — to rap, to tap
Made of: 古 old, classic, ancient 攵 to rap, to tap
How it's built: Phono-semantic — one part hints at the meaning, another at the sound

此地地势低洼，雨季排水困难，故不宜建设地下仓库。 Cǐ dì dìshì dīwā, yǔjì páishuǐ kùnnán, gù bù yí jiànshè dìxià cāngkù. This area is low-lying and has drainage difficulties in the rainy season; therefore, it is unsuitable for building an underground warehouse.
由于天气不好，航班延误，故乘客只能在机场等候。 Yóuyú tiānqì bù hǎo, hángbān yánwu, gù chéngkè zhǐ néng zài jīchǎng děnghòu. Because of bad weather the flights are delayed, so passengers can only wait at the airport.
本店今天装修，故暂停营业，请大家谅解。 Běn diàn jīntiān zhuāngxiū, gù zàntíng yíngyè, qǐng dàjiā liàngjiě. This shop is being renovated today, so it is closed for now; please bear with us.