Subject + 很 + 危险 / 遭遇 + 危险
危险 (wēixiǎn) means "dangerous" or "danger" and can function as both an adjective and a noun. As an adjective it describes risky situations, and as a noun it refers to danger itself. Common usages include 很危险 (very dangerous) and 遭遇危险 (to encounter danger).
暴风雨天气开车非常危险。
Bàofēngyǔ tiānqì kāichē fēicháng wēixiǎn.
Driving in a rainstorm is very dangerous.
前面的桥坏了,过去很危险。
Qiánmiàn de qiáo huài le, guòqù hěn wēixiǎn.
The bridge ahead is broken; it's very dangerous to cross.
孩子一个人在河边玩太危险了。
Háizi yí ge rén zài hé biān wán tài wēixiǎn le.
It's too dangerous for a child to play by the river alone.