His sister enjoys _______ tennis in her free time.
A:playing
B:plays
C:play
从远古时代开始,人们就把“天”作为人类智慧追索的对象,诗人屈原曾提出172个“天问”。下列选项中,具有唯物主义倾向的是( )
①天行有常,不为尧存,不为桀亡 ②天地合而万物生,阴阳接而变化起
③天地万物都是“绝对精神”的产物 ④存在即被感知
龟和兔在路程为S0的一段平直赛道上进行赛跑竞技比赛,它们赛跑的路程﹣时间图象如图所示,下列说法正确的是( )
John shut everybody out of the kitchen ______ he could prepare his grand surprise for the party.