1.The United States has expressed concern about an arms build-up in Venezuela saying it poses a serious challenge to stability.
美国对委内瑞拉的武器积累表示担忧。美国表示，这对稳定提出了一个严峻的挑战。
2.Today, we face another serious challenge provoked by the sinking of the South Korean ship, '' she said at the opening ceremony.
“如今，韩国天安号警戒舰的沉没，促使我们面对另一个严峻的挑战，”她在会议开幕式上表示。
3.In the Senate, 12 Democratic incumbents are seeking re-election, and only one seems to be facing a serious challenge.
在参议院，有12名现任民主党参议员正在争取连任，其中仅一人似乎遇到了严重的挑战。
4.The only movement that posed a potentially serious challenge to the regime was the short-lived China Democracy Party (CDP).
现政权曾经面临的唯一一次严重挑战是历时短暂的中国民主党（CDP）运动。
5.As a high-school student, I was abnormally shy, so as you might imagine, my sophomore speech class was a serious challenge for me.
在我还是大学生的时候，我是一个非常害羞的人，如你所能想到的，大学二年级的演讲课程对我来说是一个严重的挑战。
6.Both, though, imagine the world as it appeared after the collapse of communism removed the only serious challenge to US primacy.
尽管二人都以为——就如共产主义瓦解后看起来的那样——世界消除了对美国优势地位唯一的真正挑战。
7.Among the criticisms is a quiet but serious challenge: the artificially high number of Chinese men compared with Chinese women.
各种批评声中一个平静而严肃的挑战是，中国男女人口比例被人为地提高。
8.It's human nature to worry, but try not to be a slave to worrywart-ism (a serious challenge for me! ).
担忧是人类的本性，但是尽量不要让自己被自寻烦恼所奴役（对我而言那是一个严重的挑战！）
9.The possibility of making progress would be a serious challenge even if negotiations began tomorrow.
即便双边会谈明天就开始，对双方而言，取得进展的可能性都是一个严峻的挑战。
10.Spokesman Won says the launch would be a provocation that poses a serious challenge to regional security.
韩国国防部发言人元泰载说，这次发射将是一次挑衅行为，并对地区安全构成严重威胁。