tense問題

Which are 較好
除非你想說你現在已不覺得enjoyable and meaningful

如果用which were, 意思即你只是當時(過去)感到enjoyable and meaningful
用which are的話 (present tense), 意思即 volunteer services 令你現在和過去亦令你感到enjoyable and meaningful

例子:
This is Hello Kitty, which was my favourite character.
(Hello Kitty 是我以前最喜愛的卡通人物)
This is Hello Kitty, which is my favourite character.
(Hello Kitty 是我最喜愛的卡通人物) 現在和過去

These clothes were my mother's, which were too big when I was 12.
(這些衣服對當時12歲的我來說太大了)
These clothes were my mother's, which are too big to me.
(這些衣服對我來說太大了)

另外 visit the elderly who live alone
寫成 visiting elderly who live alone 較好

I participated in various kinds of voluntary services like fag-selling and visiting the elderly who lived alone which are enjoyable and meaningful.

Remarks : (1) volunteer(n.)-----person who offers to do something for people willingly without reward. (2) voluntary(adj.)-----doing or ready to do things,willingly.

你之後仲會唔會做義工？如果會

I have participated in volunteer services, which are enjoyable and meaningful, including selling flag and visiting the living-alone elderly.

2006-11-08 15:42:32 補充：
living-alone elderly 不是亂吹的http://www.thestandard.com.hk/news_detail.asp?pp_cat=11&art_id=13845&sid=6990559&con_type=1

應該用which were
因為你之前mention "various volunteer services "
係plural (眾數)

不過我suggest你將句子改成:
I participated in various enjoyable and meaningful volunteer services including flags selling and visit the elderly who live alone.

因為如果你寫:
I participated in various volunteer services including flags selling and visit the elderly who live alone which were enjoyable and meaningful.
會令人有一個誤會,
以為你話d老人( elderly) 獨居好 enjoyable and meaningful

I rewrite your sentence to,

I participated in various enjoyable and meaningful volunteer services, such as flags selling and elderly visit.

2006-11-09 09:26:05 補充：
Consolidate all the input the best sentence should be,I participated in various enjoyable and meaningful volunteer services, such as flags selling and living-alone elderly visit.