在一个密闭容器中,有甲、乙、丙、丁四种物质在一定条件下充分反应后,测得反应前后各物质的质量如下表:下列说法错误的是()
A:该反应是分解反应
B:甲可能是该反应的催化剂
C:乙、丙变化的质量比为9:8
D:反应后甲的质量为0g
I w____ to Qingdao with my parents last summer holiday. We t____a plane there. We went to the beach. It was very b ____. I like swimming very much. I s____in the sea. My mum took many p____ there. We had a good time.
1949年初,苏联外交部长在联合国大会上发表声明:“美国现在正以经济方式向东欧国家渗透,因此,我们不得不采取必要的措施对其回击,以巩固我们的社会主义阵营。”苏联和东欧国家采取的措施是( )
下列关于克隆的叙述错误的是( )