Original sentence: He was succeeded by Cathie Black in January 2011
Edited sentence: He was succeeded by Cathie Black in January 2011 and, immediately after that, by Dennis Walcott in April 2011.Klein brought a penchant for radical transformation to the New York City public schools, redrawing the basics of how schools are run, opening hundreds of new schools and closing dozens of others, and reeling in millions of new dollars in new funding.The high school graduation rate rose under his tenure, but other statistics cast doubt on his claims of dramatic student achievement growth