But science does provide us with the best available guide to the future, and it is critical that our nation and the world base important policies on the best judgments that science can provide concerning the future consequences of present actions.”

生詞

• provide: 提供

• guide: 指南

• available: 可用的

• critical: 關(guān)鍵的

• base: 基礎(chǔ)

• concerning: 關(guān)于

語句分析；分3個部分

主干：But science?does?provide?us with the best?available?guide?to the future,?

主干：and it?is?critical?

定語從句：that our nation and the world?base?important policies?on the best judgments

同位語從句：that science?can provide?concerning?the future consequences of present actions.

翻譯：但科學家提供給我們最好的可用的未來指南并且這，對于我們國家和世界必須在最佳判斷上是重要的政策，科學家能提供在未來行動的結(jié)果對現(xiàn)在的的影響