Let's go gau-wu (i.e. shopping) in Mongkok tonight!
Cantonese
火车呜呜声咁响。
火車嗚嗚聲咁響。
The train makes a toot-toot sound.
Examples (Wiktionary)
Mandarin
呜呼！其真无马邪？
嗚呼！其真無馬邪？
wū hū ！ qí zhēn wú mǎ yé ？
Alas! Is there really no thousand-li horse?
Mandarin
时候既然是深冬；渐近故乡时，天气又阴晦了，冷风吹进船舱中，呜呜的响，从篷隙向外一望，苍黄的天底下，远近横着几个萧索的荒村，没有一些活气。
時候既然是深冬；漸近故鄉時，天氣又陰晦了，冷風吹進船艙中，嗚嗚的響，從篷隙向外一望，蒼黃的天底下，遠近橫着幾個蕭索的荒村，沒有一些活氣。
shí hou jì rán shì shēn dōng ； jiàn jìn gù xiāng shí ， tiān qì yòu yīn huì le ， lěng fēng chuī jìn chuán cāng zhōng ， wū wū de xiǎng ， cóng péng xì xiàng wài yī wàng ， cāng huáng de tiān dǐ xià ， yuǎn jìn héng zhe jǐ ge xiāo suǒ de huāng cūn ， méi yǒu yī xiē huó qì ．
It was the deep winter as I approached my hometown- the weather was dark and gloomy. A cold wind blew into the cabin of the ship, whistling. Looking out from a gap in the awning, desolate ghost towns as far as the eye could see without a hint of life, all beneath a greenish yellow sky.