从北京奥运会的9秒69,到柏林世锦赛的9秒58,牙买加运动员博尔特8月16日重新定义了人类百米的最快速度。一名法国科学家曾断言,百米跑的最终极限应是9秒726。而如今博尔特已经两次将这一极限打破。这位科学家的断言被打破表明: ( )
However, at times this balance in nature is disturbed, _______ a number of possibly unforeseen effects.
I want an assistant with _______ little knowledge of French and _______experience of office routine.
—How nice it tastes! —In fact,this delicious cake is not difficult________.
One of the greatest benefits of stamp-collecting is that they are based on common interests,________ appearance,age or wealth.
It is ________ he often fails in exams ________ makes his parents worried about him.