PHRASAL VERB (设置警戒线)包围，警戒，封锁 If police or soldiers cordon off an area, they prevent people from entering or leaving it, usually by forming a line or ring. (设置警戒线)包围，警戒，封锁
Police cordoned off part of the city centre. [VERBPREP. noun]
警察封锁了市中心的部分地区。
The police cordoned everything off. [VERB noun PREP.]