猛不防

měng bu fáng hòu miàn yǒu rén tuī le tā yī xia

猛不防后面有人推了他一下。

Someone gave him an unexpected shove in the back.

měng bu fáng bèi zhuàng dǎo

猛不防被撞倒

be knocked down unexpectedly

yǒu rén měng bu fáng cóng hēi yǐng lǐ tiào chu lai xià le wǒ yī tiào

有人猛不防从黑影里跳出来，吓了我一跳。

Someone came out of the dark unexpectedly and gave me quite a start.

měng bu fáng yǒu rén zhuā zhù le wǒ de bó zi

猛不防有人抓住了我的脖子。

All of a sudden someone grabbed me around the neck.