how to say hello and learn some polite spoken chinese

EASY CHINESE LEARNING WITH DEMI

第一课【你好】Chinese learning with Demi

如鱼得水[rú yú dé shuǐ]：like/fish/get/water；as fish getting to the water
This idiom is used to signify finding a boon companion or an ideal situation.
东汉末年 dōng hàn mò nián：In the late Eastern Han Dynasty
诸葛亮zhū gě liàng ：a statesman and strategist, prime minister of the Kingdom of Shu in the period of the Three Kingdoms.
刘备 liú bèi ：the founder of Han kingdom in the Three Kingdoms.
关羽 guān yǔ ：a general allied to Liu Bei, deified as God of War.
张飞 zhāng fēi：a general of the Three Kingdoms.
军师 jūn shī：military counsellor；
指点 zhǐ diǎn：give advice (directions);show how to do sth.
形势 xíng shì：situation；condition
提高tí gāo：improve；raise；increase
亲密 qīn mì：close； intimate:
服气 fú qì：be convinced
例如：在这个工作环境中，他如鱼得水，非常享受工作。
           zài zhè gè gōng zuò huán jìng zhōng,tā rú yú dé shuǐ,fēi cháng xiǎng shòu gōngzuò 。
           在游泳池里，他如鱼得水，游得非常快乐。
           zài yóu yǒng chí lǐ,tā rú yú dé shuǐ, yóu de fēi cháng kuàilè 。

乐读中文 (Lè Dú Zhōngwén) - "Joyful Chinese Stories"

如鱼得水 [rú yú dé shuǐ]

画龙点睛 [huà lóng diǎn jīng]：draw;paint/loong/touch lightly /eyes；
The idiom means bringing the painted dragon to life by putting in the pupils of its eyes,and it  emphasizes the critical adjustment or embellishment made after completing a task to achieve the best possible outcome.
南北朝 nán běi cháo：The Northern and Southern Dynasties in Chinese history
画家 huà jiā：painter
张僧繇 zhāng sēng yáo：A famous ancient painters
寺庙 sì miào：temple
墙壁 qiáng bì：wall
说大话 shuō dà huà：brag；boast；talk big
顿时 dùn shí：suddenly；at once
电闪雷鸣 diàn shǎn léi míng：the lightning flashed and thunder crashed
腾空 téng kōng：rise high into the air; soar

画龙点睛 [huà lóng diǎn jīng]

对牛弹琴[duì niú tán qín]：to;towards/cattle;ox/play/lute
 The idiom means taking to someone and expecting them to care or do something instead the other person just stands there and is not responding to you.
公明仪 gōng míng yí：a person‘s name in Ancient 
出游 chū yóu：Travel; go on a tour
清澈 qīng chè：Limpid; clear
景色 jǐng sè：scenery; view; scene
兴致大发 xìng zhì dà fā：interest ; mood
尽管 jǐn guǎn：although;while;when
动人 dòng rén ：moving；touching


对牛弹琴[duì niú tán qín]

得过且过[dé guò qiě guò]：get/pass by/for the moment/pass by. 
五台山 wǔ tái shān：Mount Wutai in China
寒号鸟 hán háo niǎo：A kind of bird
浑身 hún shēn：all over;from head to foot
羽毛 yǔ máo：plume;feather
得意地 dé yì de ：proudly
凤凰 fèng huáng：a Chinese phoenix
不如 bù rú：not as good as
搭窝 dā wō：build a nest
脱落 tuō luò：drop;fall off;come off;shed
无可奈何 wú kě nài hé：helpless; against one's will
哀号 āi háo：cry piteously; wail
This idiom means to get on in a haphazard way with no clear plan and if it can pass then pass it.
eg：如果我们不努力工作，得过且过，总有一天会后悔的。
       rúguǒ wǒmen bù nǔlì gōngzuò,dé guò qiě guò,zǒngyǒu yī tiān huì hòuhuǐ de.

得过且过[dé guò qiě guò]

胸有成竹[xiōng yǒu chéng zhú]：chest;mind/has/become/bamboo；to have a well-thought-out plan；have a preconceived idea at heart; have a well-thought-out plan beforehand;
eg：他对明天的考试胸有成竹。 tā duì míngtiān de kǎoshì xiōng yǒu chéng zhú。
         我的朋友总是胸有成竹。wǒ de péngyou zǒngshì xiōng yǒu chéng zhú 。
宋朝 sòng cháo：Song dynasty
文与可 wén yǔ kě：the name of a person
画家 huà jiā：painter; artist
房前屋后 fàng qián wū hòu：In front and behind the house
形态 xíng tài：form;shape;pattern
生动 shēng dòng：vivid;lively
逼真 bī zhēn：lifelike;true to life
形象 xíng xiàng：image;form;figure