你說的對,because應該改成that.
后面的that makes life worthwhile 是一個定語從句,是正確的.
全句是：The most importnat reason why governments should support art is that an appreciation of art is one of the things that makes life worthwhile.我有點搞不清that makes life worthwhile 是修飾 things的還是修飾appreciation的，如果是修飾things的就應該把單三改為 that make 吧？你又說對了，that make life worthwhile 是修飾先行詞things 的，因此，makes 應該改成make.是我粗心了。