找错喽We are looking forward to see you at the farewell party.

we are looking forward to seeing you at the farewell party.

look forward to doing 期待做某事
这里的 to 是介词
所以后面加名词，或者相当于名词的词语，如动词的现在分词形式

see→seeing

We are looking forward to seeing you at the farewell party.

Look forward to doing sth

to是介词