放冷箭
Stab in the back.

【发音】fàng lěng jiàn

【释义】（惯）喻指暗中加害于人的行为或手段。又称“射冷箭”。
            Used as a metaphor to refer to playing tricks behind sb.'s back, or secretly getting sb. into trouble.

【例1】他就会背后放冷箭，真让人火大。
           He often stabs people in the back, which enrages me.

【例2】卑怯而狡猾的懦夫则往往想要暗中施放的冷箭。
           Base and crafty cowards, are like the arrow that shoots in the dark.

打破沙锅问到底
Insist on getting to the bottom of the matter.

【发音】dǎ pò shā guō wèn dào dǐ

【释义】问：同“璺”谐音；指陶瓷或玉石等器皿上的裂纹或裂缝。比喻对事情寻根究底。
            In Chinese, inquiring shares the same pronunciation with “crack” which is in pottery or jade. The phrase indicates one’s perseverance on questioning and finding out the truth.

【例1】那位采访者打破沙锅问到底，不过该政府发言人丝毫没有放松警惕。
           The interviewer asked some very searching questions but the government spokesman didn't drop his guard for a second.

【例2】小明老爱问为什么，老爱打破砂锅问到底。
           Xiao Ming always asks why and he'll never be satisfied until he knows everything.

动不动
Easily.

【发音】dòng bú dòng

【释义】跟“就”连用，表示容易发生某种情况或行动。
            This phrase means someone is easily inclined to do something.

【例1】他就是这么婆婆妈妈的，动不动就掉眼泪。
           He's such a sissy he easily breaks down and cries.

【例2】他动不动就对别人横加指责，气势逼人。
           He's always making unwarranted accusations against others. His manner is intolerably aggressive.

顶呱呱
First-rate.

【发音】dǐng guā guā

【释义】形容质量或表现好极了。
            The quality of goods or performance is excellent or extremely good.

【例1】在毕业生中她是顶呱呱的一个。
           She is second to none among all the graduates.

【例2】这件毛衣的质量真是顶呱呱！
           The quality of this sweater is excellent!

  
National Day (guó qìng jié 国庆节) originally refers to the good or festive time. In ancient times of China, the most festive thing of one country must be the new emperor enthroned or the birthday of the king, which was regarded as the National Day. Since the People’s Republic of China was founded on October 1, 1949 with a ceremony at Tian’anmen Square, the Central People’s Government passed the Resolution on the National Day of the PRC (guān yú zhōng huá rén mín gòng hé guó guó qìng jié de jué yì 关于中华人民共和国国庆日的决议) on December 2, 1949 and declared that October 1 is the National Day.