By Paula Wolfson

The focus in the U.S. presidential campaign shifted to taxes and science Monday, as new polls showed a tight race. Both President Bush and the Democratic Party presidential nominee John Kerry were wooing voters in key states.

On the day two Americans were awarded the Nobel prize for medicine, Senator Kerry took issue with the Bush administration's stand on stem cell research.

Mr. Kerry sharply criticized the president's decision to restrict federal research on cells from human embryos. They are called stem cells, because they can assume all sorts of functions in the human body.

Some researchers say they may hold the key to cures or treatments for a number of debilitating diseases and conditions, from paralysis to juvenile diabetes.

Senator Kerry told an audience in New Hampshire that the president is forsaking potentially life-saving science in order to please conservatives who say using embryos for research is tantamount to abortion.

"When it comes to stem cell research, this president is making the wrong choice to sacrifice science for extreme right-wing ideology," he said.

Mr. Kerry spoke at a town hall style event - where voters directly question the candidate. It is the format that will be used at the second presidential debate on Friday. President Bush also took part in a town hall event Monday. The site was an auditorium in Iowa, and the main subject was taxes.

"And there is a difference on taxes in this campaign. There is a big difference. I have lowered taxes and my opponent wants to raise taxes."

Shortly after arriving in Iowa, the president signed legislation to extend the life of tax cuts set to expire next year. They include reductions for families with children, and married couples with two wage earners.

On Tuesday, the two major party presidential nominees will cede the spotlight to their running mates. Republican Dick Cheney and Democrat John Edwards will meet for their one and only vice presidential debate in Cleveland, Ohio.

Paula Wolfson, VOA News, the White House.

注释：
embryos 晶胚
debilitate 削弱
paralysis 瘫痪
juvenile 麻痹
New Hampshire 美国新罕布什尔州
legislation 立法，法律