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。

youdao

Arms are a challenge because they make the robots more expensive, more difficult to use and less stable, analysts say.

分析师表示，机械手臂会使机器人的造价更高、使用上更困难、更不稳定，因此是一大挑战。

youdao

But Lanza sees his work as more than a challenge, or a call to arms.

FORBES: Sciences and Medicine

On the most immediate challenge, working out an arms control agreement to replace the START I treaty which expires December 5, the two presidents signed a joint understanding for a follow-on agreement to START that commits both parties to a legally binding treaty that will reduce nuclear weapons.

CNN: Obama moves to bolster U.S.-Russia ties

Many of the states that would have to enforce a small-arms accord are too weak (partly because of the challenge they face from armed rebels or criminals) to do so.

ECONOMIST: Hey, anybody want a gun?