重點(diǎn)講解：
1. on alert 處于警戒狀態(tài)；保持戒備；
例句：Security forces were placed on alert.
治安警備力量進(jìn)入了警戒狀態(tài)E^WqcbzWN7Jij.Gd。
2. turn over (使)翻轉(zhuǎn)；(使)顛倒；(使)傾覆；
例句：Liz picked up the blue envelope and turned it over curiously.
莉茲拿起藍(lán)色信封，好奇地翻過來看V_^U)%C4mAO~thle。
3. to be honest 老實(shí)說；說實(shí)在的；
例句：To be honest, I have stopped reading papers for years now.
實(shí)話說，我已經(jīng)好幾年不看報(bào)紙了Mr624T9M_rMyFe0y.%o#。
4. under threat 受到威脅；
例句：The biologist believes that some animal species are under threat of extinction.
那位生物學(xué)家相信某些動(dòng)物物種正受到滅絕的威脅r6X=&7d8l9TMe。
5. even though 即使；盡管；縱然；
例句：I don't like spinach even though I know it's good for me.
我不喜歡吃菠菜，雖然我知道它對(duì)我有好處Q*#j~b^eR1o6.9t#w。