【1】attend一般用于正式场合，主要指正式参加/出席比较正式的婚礼/葬礼场/很重要会议场合。

Thousands of people attended the funeral.数千人参加了葬礼。

Tom is going to  attend Mary’s wedding next Monday汤姆下个星期一将参加玛丽的婚礼 。

The meeting will be attended by finance ministers from many countries.很多国家的财政部长将出席会议。

Several maidens were invited to attend her wedding. 好几个少女被邀请去参加她的婚礼。

【2】come to主要用于一般性参加/出席普通性聚会或者生日派对。

Would you like to come to the party in my house tonight?  你愿不愿意今晚到我家参加晚会?

Come to the party and bring some friends along.  请来参加聚会并带些朋友来.

Though he was late,he came to the birthday party. 他虽然迟到，还是来参加生日宴会了。

 How many people do you expect to come to the birthday party?  您打算请几位客人出席生日晚会?