示范答案：
I used to teach in a school which had 1,600 students, aged from 11 to 18. The majority of the children aged from 11 to 16 remained in school all day and if they had to leave，they did so via the school office and the main entrance. The school was situated in the centre of the town and was always in danger of having intruders. The students aged from 16 to 18 were allowed to leave whenever they pleased by an exit far from the main office. This exit/entrance remained open throughout the day and therefore intruders could get in.
The proposal I made was that the open gate should be replaced by a high security sliding gate. The gate would open for a fixed period after a student used a swipe plastic card to activate the opening mechanism. I got the idea from the type of cards used in hotels to replace room keys. Cards could easily exclude intruders from the system by having the whole system linked to a computer. The system would have also kept a computerised record of the movement of each student in and out of the building. If a student forgot his/her card，they would have to exit via the main entrance and the school office.
Sadly, my idea was not adopted because of the cost and the fact that the students objected a computerised record of their entries and departures from the school.
