[dc sort] editorial work

sorting/dc-sort/dcsort-en.tex

@@ -2785,7 +2785,7 @@ \section{Short summary}
 
 We've shown some elementary sorting algorithms in this book till this chapter, including
 insertion sort, tree sort, selection sort, heap sort, quick sort and merge sort. Sorting
-is still a hot research area in computer science. At the time when I this chapter is written,
+is still a hot research area in computer science. At the time when this chapter is written,
 people are challenged by the buzz word `big data', that the traditional convenient method
 can't handle more and more huge data within reasonable time and resources.
 Sorting a sequence of hundreds of Gigabytes becomes a routine in some fields.