A：水是一种化合物
B：水是由两个氢原子、一个氧原子构成
C：水分子由氢、氧两种原子构成
D：水是由氢、氧两种元素组成的
下列能够正确表示蟾蜍发育过程的是（ ）
Jenny and Li Ming watched Bob play basketball this evening. They arrived at the gym(体育馆)at 6：30. Bob's team played with the Orange Team. Everyone played hard! Jenny and Li Ming had fun at the gym. They yelled for Bob's team. Finally, Bob's team won. They were very happy.
“这是一个具有高度标志性的事件，它表明中国的航天技术在21世纪已经走到了欧洲和日本前面。”这一评论是指( )
古往今来，人们一直在赞美青春，歌颂青春。下列句子体现要珍惜青春的是（ ）
①盛年不重来，一日难在晨。及时当勉励，岁月不待人 ②莫等闲，白了少年头，空悲切
③青春易逝，人生易老，当及时行乐 ④劝君莫惜金缕衣，劝君惜取少年时
