下列物质在元素组成上最相似的一组是[ ]
A.糖原、胰岛素、性激素
B.纤维素、维生素C、叶绿素
C.淀粉、淀粉酶
D.DNA、RNA
答案:D
The US President Obama told the students that he ______ by a single mother who were strict with him and wished him great success in his studies.
A.will have been brought down
B.has been carried out
C.was brought up
D.was about to be cared for
一般来说,大班幼儿所处的游戏水平是()。
A.独自游戏
B.平行游
C.联合游戏
D.合作游戏