seeing off常在介詞後,seeing作動名詞,off作形容詞修飾,另seeing-off ceremony,seeinf-off是形容詞修飾後面名詞,請益.謝謝.?

off--preposition (used in numerous compound-words)
eg:-seeing-off
Also adverbial particle such as seeing-off in the verb entry;
seeing-off is contrasted with on, indicating the ending of something arranged, planned, etc
eg:- The seeing-off of the ceremony=ended.

see off 動詞片語，其中off 是介詞，為某人送行。而seeing-off 是複合形容詞由動名詞+介詞合成，修飾其後名詞，意思為告別式，两个截然不同

to see someone off: 及物動詞＋受詞＋受詞補語
off是副詞，表示移動離開，在上面是當作受詞補語用。

see someone off = accompany a person to the point of departure
They came to the station to see him off.
see p.1580 New Oxford American Dictionary (third edition)

a seeing-off ceremony = a ceremony in which you see someone who is leaving their present job/place

seeing是自「及物動詞see」衍生的「動名詞」，用連字號加上副詞off，放在名詞ceremony前，形成一個「複合名詞」（noun compound）。

類似的「複合名詞」有：
a waiting list
a swimming pool (= a pool in which you can swim)
a shopping center
a writing desk

~ing有可能是現在分詞，當作形容詞用，如：
a dancing girl = a girl who is dancing now
這詞的主重音落在後面的名詞girl上。
主重音大聲又清楚，次重音清楚但不大聲，弱音節的母音模糊或省略。

~ing如果是動名詞，和後面的名詞形成「複合名詞」時，意思就不同了：
a dancing girl = a girl whose job is to dance with someone else
這詞的主重音落在前面的動名詞dancing上。

由分詞片語所形成的「複合形容詞」
a broken-down car = a car which has broken down
a laid-off worker = a worker who has been laid off