NEW YORK - Donald Trump rejected criticism from the father of a soldier killed in Iraq who said the Republican presidential nominee had "sacrificed nothing and no one" and questioned whether the mother was allowed to speak during the couple's appearance at the Democratic convention."I think I've made a lot of sacrifices," Trump told ABC News in excerpts of an interview posted on Saturday. "I work very, very hard."Khizr Khan, a US citizen of Pakistani origin and a Muslim, won widespread praise when he spoke Thursday at the Democratic National Convention, telling the story of his son, US Army Captain Humayun Khan, killed by a bomb in Iraq in 2004.He also attacked Trump for proposing a temporary ban on Muslims entering the United States and asked if the candidate had read the US Constitution. He pulled out a pocket-copy from the inside of his suit coat, in one of the most commented moments on the night that Hillary Clinton accepted her party's nomination for president."Did Hillary's script writers write it?" Trump asked ABC's George Stephanopoulos in the interview. He said he has indeed sacrificed by employing thousands of people, and raising "millions of dollars" for veterans.Trump said Khan appeared "very emotional and probably looked like a nice guy to me."But the businessman also cast doubt on why Khan's wife did not speak."She was standing there, she had nothing to say, she probably, maybe she wasn't allowed to have anything to say, you tell me," Trump said.Clinton said in a statement on Saturday that she was "very moved to see Ghazala Khan stand bravely and with dignity in support of her son on Thursday night. And I was very moved to hear her speak last night, bravely and with dignity, about her son's life and the ultimate sacrifice he made for his country."Ghazala Khan told MSNBC on Friday that she chose not to speak because she still cannot bear to see her son's photographs. Khizr Khan told the New York Times that the Clinton campaign asked if he need speechwriting help or coaching."I said: 'I really don't, I have my thoughts in my head,'" Khan told the Times, adding, "'Just let me say what I want to say. It will be heart-to-heart'."