How should i say the following in chinese?
1. Good morning
2. Good evening
3. Good afternoon
4. Good night
5. What are you doing?
6. You're welcome
7. I'm sorry
8. Excuse me
9. I understand
10. no
11. yes
12. big sister
13. cousin
14. have you eaten your meal?
15. breakfast
16. lunch
17. dinner
18. snack
19. i care for you
20. i am doing good
21. i hate you
22. i am eating. how about you?

Question

Answer

1. Good morning————早上好[zǎo shàng hǎo]
2. Good evening————晚上好[wǎn shàng hǎo]
3. Good afternoon————下午好[xià wǔ hǎo]    
4. Good night————晚安[wǎn ān]
5. What are you doing?————你（现在）在做什么?[nǐ （xiàn zài） zài zuò shén me] 
6. You're welcome————不客气[bú kè qì]
7. I'm sorry————对不起[duì bù qǐ]
8. Excuse me————抱歉[bào qiàn]                     
9. I understand————我懂了[wǒ dǒng le]     
10. no————不/不是[bù/bú shì] 
11. yes————是/是的[shì/shì de] 
12. big sister————姐姐[jiě jie] 
13. cousin————堂兄（弟、姐、妹）[táng xiōng(dì\jiě\mèi)]             
14. have you eaten your meal?————你吃饭了吗?[nǐ chī fàn le mā]
15. breakfast————早餐[zǎo cān] 
16. lunch————午餐[wǔ cān]  
17. dinner———— 晚餐[wǎn cān] 
18. snack————小吃[xiǎo chī]  
19. i care for you————我关心你[wǒ guān xīn nǐ]  
20. i am doing good————我在做好事[wǒ zaì  zuò hǎo shì]
21. i hate you————我讨厌你[wǒ tǎo yàn nǐ]
22. i am eating. how about you?————我在吃饭,你呢?[wǒ zài chī fàn,nǐ ne]

Answer

19. i care for you                 我在乎你 wo zai hu ni

Answer

13. cousin       ( maternal)      biao ge( elder bro) ,
                                          biaojie(elder sis) , 
                                          biao di(younger bro), 
                                          biao mei(younger sis).
                      ( patriarchal ) tang ge( elder bro),
                                          tang jie(elder sis),
                                          tang di( younger bro),
                                          tang mei(younger sis).

Answer

Lol, just wanna add something:
Have you eaten your meal? -- That would be the famous "吃了吗? (chi le ma?)"
snack -- Generally, it's more commonly called 点心 (dian xin or dim sum).  Afternoon snack is called 下午茶 (xia wu cha), and if taken late at night, it's called 夜宵 (ye xiao).
I am doing good. -- Here, the word "good" does not take on its usually meaning, but the meaning that something is progressing smoothly.  So the corresponding Chinese would be "一切进行地很顺利 (yi qie jin xing de hen shun li)".

Answer

Good morning         zao shang hao 早上好
2. Good evening      wan shang hao 晚上好
3. Good afternoon   xia wu hao    下午好
4. Good night          wan an 晚安
5. What are you doing?       ni xian zai zai zuo shen me 你现在在做什么?
6. You're welcome              bu ke qi 不客气
7. I'm sorry                        dui bu qi 对不起
8. Excuse me                     bu hao yi si 不好意思
9. I understand                  wo zhi dao le     我知道了
10. no                              bu 不
11. yes                             shi  是
12. big sister                     da jie jie 大姐姐
13. cousin                         this is one hard to say..coz cousin can be used to describe brother, sister,  
                                          : ge ge 哥哥(the elder brother)   di di 弟弟 (the brother younger than you) : jie jie  姐姐  (elder sister) : mei mei 妹妹( younger sister)
14. have you eaten your meal?        ni chi fan le ma? 你吃饭了吗?
15. breakfast                            zao can 早餐
16. lunch                                zhong can  中餐
17. dinner                                 wan can  晚餐
18. snack                                    xiao chi  小吃
19. i care for you                        wo hen guan xin ni  我很关心你
20. i am doing good                    wo zuo de hen hao.... 我做的很好
21. i hate you                             wo hen ni 我恨你
22. i am eating. how about you?     wo zai chi fan ,ni ne ? 我在吃饭,你呢?