the only 修饰名词后加to do 还是doing

the only修饰名词时，它后面习惯上可以加上动词不定式短语to do；而不宜加上doing短语；

动词不定式短语一般是用作后置定语的；

例句

Mr. William is the only foreign friend to be present at the meeting / to be invited to the meeting.

关于to do 、doing的用法

名词+to do

有些名词，其后的修饰语一般用to do；

They have no ability to win the game.

他们没能力赢得这场比赛。

名词+介词+doing

有些名词，其后通常接“介词+-ing分词”作后置修饰语，而一般不接to do；

He has little hope of passing the exam.

他没有希望通过考试。

名词+to do”和“名词+介词+doing”

除了以上两种情况所介绍的名词外，还有一些名词，后面接“名词+to do”和“名词+介词+doing”两种形式皆可以，意义上也无区别；

Although they had made an effort to finish the task, they failed at last.

=Although they had made an effort at finishing the task, they failed at last.

尽管他们已尽力完成任务，最终还是失败了。