这句话是“大句子里有小句子,语法错误” 如何修改?（保留大体结构）Therefore,this can be of great importance to the development opportunity of 21st Century contribute to social progress and individual residents alike.翻译：因此,这些是非常重要的对于 21世纪的发展机遇有助于社会和个人的发展.

Therefore, this can be of great importance to the development opportunity of 21st Century 这句话是没有问题的也不需要改成 of importance 就相当于important。强调的是这对21实际的发展机遇很重要。关键是后面的那句话，后面的那句话其实主语还是前面的this，因此动词要变成单三，因为是并列的 加上and即可。因此改成Therefore, this can be of great importance to the development opportunity of 21st Century and contributes to social progress and individual residents alike.

Therefore, this can be of great importance to the development opportunity of 21st Century which contributes to social progress and individual residents alike.(改为从句）或Therefore, this can be of great importance to the development opportunity of 21st Century contributing to social progress and individual residents alike.（现在分词）

Therefore, this can be a great and critical opportunity of the 21st Century that contributes to social progress and individual residents alike.

development能否改为developing？
Therefore, this can be of great importance to the developing opportunity of 21st Century which contribute to social progress and individual residents alike.

其实在 contribute 前面加 and 就可以了 这是并列谓语
不用改成单三 形式 ,因为是在can后面并列的 也就是共用一个can.