重点讲解：
1. beware of
小心；提防；当心；注意；
eg. Beware of being too impatient with others.
注意不要对他人太没有耐心。
eg. Motorists were warned to beware of slippery conditions.
驾驶员接到提醒当心道路湿滑。
2.take advantage of
占…的便宜；欺骗；捉弄；
eg. It never occurred to me to take advantage of him.
我决没有想到过要占他的便宜。
eg. He's joining the club in order to take advantage of the others.
他入会是来揩油的。
3. mark down
减价；降低…的价钱；
eg. Retailers will have to mark down prices sharply to bring in sales.
零售商将不得不为了提高销量而大幅降价。
eg. Clothes are the best bargain, with many items marked down.
买衣服是最划算的，许多衣服都降价了。