重點講解：
1. pick up the tab (替一群人)付賬，承擔費用；
Pollard picked up the tab for dinner that night.
那天的晚飯是波拉德掏的錢B7.ivZs1qm8;Qdu&fv。
2. trade sth. for sth. 用…進行交換；互相交換；
Tom made me an offer I couldn't refuse. He asked me to trade his computer for my old cell phone. He must be crazy!
湯姆給我提供了一個我難以拒絕的條件，他要我用我的舊手機交換他的電腦JTDCg%lNK|~q。他一定是瘋了！
3. watch out for 密切注意；戒備；提防；
He called out to them to watch out for the unexploded mine.
他沖他們大喊，叫他們小心啞雷]yRk1wYhJ]rETAT。
4. in effect 其實；實際上；
In effect, the two systems are identical.
實際上，這兩種系統完全一樣p7P#.9^(XZCHP。