It was my university friend’s wedding ceremony today.
上記の英文でも、文法は問題ありませんが、今回は、それ以外のいい方を、ひとつご紹介させて頂ければと思います。
なるべく、初級者でも使える英語にしたいので、少し日本語を変えて、
「今日は、大学時代の友達の結婚式でした」
にすると、attendを知らない方でも作れると思います。
↓
It was my university friend's wedding ceremony today.
（今日は、私の大学時代の友人の結婚式でした。）
英語にするのが、もし難しく感じられる方がいらっしゃったら、このように日本語を少し変えるだけで、他の表現もできますので、よかったら試してみてくださいね＾＾
ご参考になれば幸いです。
I attended my university friend's wedding ceremony today.
I attended a wedding ceremony of my friend from university today.は文法として問題ありませんが、もう少し自然な言い方を紹介します。
I attended my university friend's wedding ceremony today.
「大学時代からの友人」は短くにmy university friendとして訳してもいいです。
それと同じように、高校時代の友達はhigh school friendなどとなります。
I attended my university friend's wedding ceremony today.
Instead of saying " "I attended a wedding ceremony of my friend from university today."'
we should say "I attended my university friend's wedding ceremony today."
This is a better and clearer way to structure your sentence.
"I attended a wedding ceremony of my friend from university today."
というよりかは
"I attended my university friend's wedding ceremony today."
の方が、はっきりとして意味が伝わりやすいでしょう。
I attended my university friend's wedding ceremony.
I went to my university friend's wediing ceremony.
--> If you attend a meeting or other event, you are present at it.
Thousands of people attended the wedding ceremony.
I attended my university friend's wedding ceremony.
I went to my university friend's wediing ceremony.
-->イベントやミーティングにattendという動詞を使うと、そこに出席しているという意味になります。
例
Thousands of people attended the wedding ceremony.
1000人がその結婚式に参加した。
I attended my university friend's wedding ceremony.
大学の頃の友人の結婚式に参加した。
I went to my university friend's wediing ceremony.
大学の友人の結婚式に行った。
I attended a wedding today. My friend from university was getting married.
My university friend got married today and I went to their wedding.
When you attend a wedding ceremony of a university friend, and want to tell someone about it, you can say:
-I attended a wedding today. My friend from university was getting married.
-My university friend got married today and I went to their wedding.
-I went to my university friend's wedding today.
大学の友人の結婚式に出席することを誰かに言いたい場合、以下のように言えます。
-I attended a wedding today. My friend from university was getting married.
本日結婚式に参加しました。大学の友人が結婚したのです。
-My university friend got married today and I went to their wedding.
今日大学の友人が結婚し、私は結婚式に参加しました。
-I went to my university friend's wedding today.
今日大学の友人の結婚式に行きました。
I attended my university friend's wedding ceremony today.
You can change that sentence and make it shorter by replacing certain phrases such as 'of my friend'. So, I attended a wedding ceremony 'of my friend' from university, becomes 'I attended my university friend's wedding ceremony today'. A friend from university is shortened to 'my university friend'. The shorter the sentence in this case, the better.
So, you may say:
I attended my university friend's wedding ceremony today.
'of my friend'のようなフレーズを別の言葉に置き換えて文を短くすることもできます。
I attended a wedding ceremony 'of my friend' from universityを 'I attended my university friend's wedding ceremony today'にすることもできるということです。
I attended my university friend's wedding ceremony today.
今日、大学の友達の結婚式に出ました。
I attended a friend from university's wedding ceremony today.
I attended a friend from college's wedding ceremony today.
I went to a friend from university's wedding ceremony today.
The first two examples show that we can interchangeably use the words, "university," or, "college," as these both mean the same. College is more a word that is used in American English accent.
We can also use the verb, "to attend," or, "to go," in the past tense and still keep the same meaning.
日本 
アメリカ合衆国 
南アフリカ 
