古诗名句积累。
世界上充满了____。花朵里面有问号，天空、海洋和陆地都有问号。
At the end every year. ( )
已知f（x）=xlnx﹣ax，g（x）=x3﹣x+6，若对任意的x∈（0，+∞），2f （x）≤g′（x）+2恒成立，则实数a的取值范围为（ ）
In the past, jeans were just hard-wearing pants workers.
