关于艾滋病的检测、防治和研究，现有的医学及技术水平还无法达到的是（ ）

2015年5月1日开始实施的《存款保险条例》规定，存款保险实行限额偿付，向存款人最高偿付限额为人民币50万元。这一规定旨在（   ）。

2015年11月7日，海峡两岸领导人在新加坡举行“习马会”。在交谈中提及汪道涵先生所讲“两岸之道，唯和与合，势之所趋，事之必至。期我同胞，终能秉持九二共识与汪辜会谈之谛，续写协商与对话新页。”电文中提及的“汪辜会谈之谛”具体是指（    ）

       It was sunny and ____ again at this time of year. John went to the beach to ____ his weekend. He was lying on the sand and ____to music. Suddenly he ____ someone crying for help. He ____ up hurriedly and looked towards the voice. He saw a little boy waving(挥动) his hands in the____a little far away. He ____ off his clothes and jumped into the water____. He swam to the little boy, held him, kept his head ____ the water and swam back to the beach. At last, the boy was safe. He thanked John a____.

在不计空气阻力的情况下，下列运动中加点物体机械能守恒的是（   ）