turn off ,take off ,put off , keep off各是什么意思?请各举一个例句

turn off ,take off ,put off , keep off各是什么意思?请各举一个例句

关掉收音机等,起飞 脱掉衣服之类,推迟,阻止.（依次回答）
i turn off my radio.
the plane hade taken off./i take off my clothes.
please put off the meeting.
keep virus off your computer.