Correct

哀悼 vs 悼念 vs 追悼

/ āidào vs dàoniàn vs zhuīdào /
Strokes

Definition

哀悼, 悼念, 追悼 are all Verb, which means [grieve over sb.'s death].

Example

哀悼, 悼念, 追悼, the three verbs all mean to think of the dead.
哀悼 and 悼念 are used more frequently and can be used exchangeably as the object of 表示.
1
jiā
大家
duì
zhāngxiānsheng
张先生
de
shìshì
逝世
biǎoshì
表示
āidào
哀悼
  
(
dàoniàn
悼念
  
)
  

Everybody shows deep grief over the death of Mr. Zhang.

2
qīn
母亲
shìshì
逝世
le
  
,
ér
儿女
men
dōu
zài
chéntòng
沉痛
dàoniàn
悼念
  
(
āidào
哀悼
  
)
  

The mother passed away and all the children are grieving deeply for her.

3
zài
dào
悼词
zhōng
biǎoshì
表示
le
duì
wángyǒu
亡友
de
āidào
哀悼
  
(
dàoniàn
悼念
  
)
zhī
qíng
  

In the memorial speech,he expressed great condolences over his deceased friend.

追悼 is more formal and 追悼会, meaning memorial meeting,is commonly used.
4
Sūn
xiānsheng
先生
bìngshì
病逝
  
,
xuéxiào
学校
wéi
xíng
举行
le
zhuīdàohuì
追悼会
  

After Mr.Sun died of illness,the school held a memorial meeting in honor of him.

5
Zài
zhuīdàohuì
追悼会
shàng
  
,
péngyou
朋友
men
biǎoshì
表示
le
duì
zhě
死者
de
āi
哀思
  

At the memorial meeting,friends expressed their deep grief over the deceased.

At a formal occasion any of the three (哀悼, 悼念, 追悼) can be used:
6
Zài
zhuīdào
追悼
  
(
āidào
哀悼
  
)
  
(
dàoniàn
悼念
  
)
nàn
死难
lièshì
烈士
zhī
之际
  
,
jiā
大家
dōu
biǎoshì
表示
yào
chéng
继承
zhě
死者
wèijìng
未竟
de
shì
事业
  

At the moment of mourning over the martyrs, all of the people present voiced their strong will of carrying on the unaccomplished cause.