单选题 During a civil defense exercise, the police ______ the streets in ease anyone tried to leave shelter too soon.

【正确答案】 B
【答案解析】patrol巡逻；pave(给道路)铺上石块或砖；peer眯着眼看；permeate (through)渗透，穿过。句意：在一次民众防卫演习中，警察要巡查街道防止有人提早拿开护庇设施。