美国总统竞选即将以大张旗鼓的方式进行。总统竞选人巴拉克.奥巴马和麦凯恩预计将在民主党全国代表大会以及共和党全国代表大会举行前宣布他们的副总统人选。两党的全国代表大会分别于8月底和9月初举行。

Public opinion polls give Democrat Barack Obama a narrow lead over Republican John McCain, so the upcoming conventions are important for both presumptive nominees.

民意调查显示，民主党总统候选人巴拉克.奥巴马以微弱优势领先于共和党的麦凯恩，因此即将召开的两党全国代表大会对两位可望获得提名的候选人来说都是至关重要的。

President of the Pew Research Center Andrew Kohut says many voters do not pay much attention to the presidential race until the party conventions.

安德鲁.科胡特是皮尤研究中心的总裁。科胡特说，许多美国选民直到两党开全国代表大会的时候才开始关注总统竞选的选战。

"This is a very important time because people get to see these candidates up close, and they recognize that it is only a relatively short run until they have to make a decision," he said. "And for McCain it could be a period of time where he really gets an advantage in terms of coverage and exposure, which he has not had over the course of this campaign yet."

科胡特说：“这是一个非常重要的时刻，因为人们能够近距离地看到这些候选人。他们也认识到，他们在很短的时间内要作出决定。对麦凯恩来说，这一段时间是他真正能够得到报导和曝光优势的时间，这些是他在竞选过程中一直没有得到的。”

The Democrats hold their convention in Denver, Colorado, the last week of August. The Republicans hold theirs the following week in Minneapolis-St. Paul, Minnesota.

民主党将于8月最后一个星期在科罗拉多州的丹佛市举行全国代表大会。共和党在那之后的一个星期在明尼苏达州的明尼阿波利斯/圣保罗举行共和党全国代表大会。

Both candidates will be looking for a post convention bounce, or boost, in public opinion polls that will carry them into the general-election campaign between September and the election on November 4.

两位候选人在代表大会后都希望看到民调反弹或是提升，并希望在9月份到11月4号总统大选投票期间能够保持这一势头。

Norman Ornstein, a political scholar at the American Enterprise Institute in Washington, expects the presidential race to remain close and says both presumptive nominees have challenges at their respective conventions.

诺曼.奥恩斯坦是总部设在华盛顿的美国企业研究所的政治学者。奥恩斯坦预计这次总统大选的竞争将会保持势均力敌的势头。他说，两位可能被提名的候选人都在各自政党的全国代表大会上面临挑战。

"And it is likely to stay that way because this is an election that in effect is about whether Obama can get over the threshold of acceptability at a time when people want change," he said. "And McCain is not the incumbent, but he is much more closely identified as the status quo."

他说：“很可能会维持这种状态，因为这场选举实际上是关于奥巴马是否能跨过一个关口，也就是在人们要求变革的时刻人们会不会接受他。麦凯恩不是现任官员，但是人们把他和当前的现状更密切地联系在一起。”

Both contenders are expected to announce vice presidential running mates before the conventions begin. Neither candidate has given any strong indications as to who his running mate will be.

两名候选人都可望在党代表大会开幕之前宣布副总统竞选夥伴。两位候选人目前都没有任何迹象显示他们的竞选搭档是谁。

The four-day political conventions will give both Obama and McCain a chance to re-introduce themselves to the voting public, and to cast their opponent in negative terms.

为期四天的全国代表大会将给予奥巴马和麦凯恩一个机会，让选民了解自己，并且为对手涂抹负面色彩。

"There is a truism in American politics, which is that the candidate who is able to define himself and define his opponent first wins the election," said Peter Brown, who does polling on the presidential race for Quinnipiac University in Connecticut. "This is an election that is about Senator Obama, and the question is who will be able to define Senator Obama for these voters we are talking about first and better, Senator Obama or Senator McCain."

彼得.布朗为康涅狄格州的昆尼皮亚克大学进行总统竞选方面的民调。布朗说：“在美国政治中有一点是不言而喻的，那就是能够首先界定自己并且界定对手的候选人能够在选举中获胜。这次选举是关于参议员奥巴马，问题是谁能首先并且更好地为我们谈到的这些选民界定参议员奥巴马或参议员麦凯恩。”

Senator McCain faces the challenge of putting some political distance between himself and President Bush, who continues to get low public-approval ratings in voter surveys.

麦凯恩参议员面临的挑战是要把自己和美国总统布什之间保持一定的政治距离。布什总统的民调支持率仍然持续低迷。

But Senator Obama has issues as well. Pollster Andrew Kohut told VOA's Press Conference USA program that Obama is still having difficulty in winning over some supporters of former Democratic rival Hillary Clinton.

但参议员奥巴马本身也有问题。民调专家安德鲁.科胡特在美国之音的一个新闻节目上说，奥巴马在赢得前民主党对手希拉里.克林顿的支持者方面仍然有困难。

"Hillary Clinton supporters are still not fully onboard with Barack Obama," he said. "Just 72 percent of Clinton supporters say they are going to vote for Obama. Eighty-five or 86 percent of the supporters of McCain's former opponents are with him. So, Obama has not quite closed the deal."

科胡特说：“希拉里的支持者还没有完全赞同巴拉克.奥巴马。72%的克林顿的支持者说，他们会投票给奥巴马。 而麦凯恩的前党内竞选对手的支持者中，有85%或86%的人表示愿意投票给麦凯恩。因此，奥巴马的大局仍然未定。”

Senator Clinton is getting a prominent speaking role at the Democratic convention, as is her husband, former President Bill Clinton, and Michelle Obama. Senator Obama will formally accept his party's nomination at an outdoor football stadium on the fourth night of the convention.

参议员克林顿将在民主党全国代表大会成为最突出的发言者之一。除了克林顿参议员之外，她的丈夫、美国前总统比尔.克林顿，和奥巴马的夫人米歇尔.奥巴马的发言也同样令人关注。参议员奥巴马将在民主党全国代表大会的第四天晚上在一个室外足球场正式接受民主党的总统候选人提名。

President Bush will speak at the Republican convention in Minnesota, but will do so early in the week so that the focus can shift to the presumptive nominee, Senator McCain and his yet to be chosen running mate.

布什总统将在明尼苏达州举行的共和党全国代表大会上发言。但是他将会在那个星期的早些时候发言，以便让重点转移到可能获得党内提名的麦凯恩和他尚待公布的竞选搭档身上。