春秋战国时期由于生产力的发展,促使社会不断变革,最终导致奴隶制度的瓦解,封建制度的确立。那么,最能代表当时生产力发展水平的是( )
A:青铜器的广泛使用
B:水利事业的发展
C:铁农具、牛耕的使用和推广
D:耕作技术的提高
Picture
Description(描述)
____.
A. They're very smart. People kill them for their ivory.
____
B. Do you often watch him play basketball? If you do so, what do you think of him?
C. —I can't find my keys.
—Let me help you.
D. It's good exercise and also it's good for our environment (环境).
E. I always get up at 6 o'clock in the morning.
F.It means that you can't take photos.
- Where is your mother?
- ___________.( )
某校从参加高一年级期中考试的学生中随机抽出60名学生,将其数学成绩(均为整数)分成六段40,50),50,60),…,90,100后得到如图所示的频率分布直方图,观察图形的信息,补全这个频率分布直方图后,估计本次考试中的平均分(统计方法中,同一组数据常用该组区间的中点值作为代表) ( )
按要求答题。
孙权劝学 初,权谓吕蒙曰:“卿今当涂掌事,不可不学!”蒙辞以军中多务。权曰:“孤岂欲卿治经为博士邪?但当涉猎,见往事耳。卿言多务,孰若孤?孤常读书,自以为大有所益。”蒙乃始就学。及鲁肃过寻阳,与蒙论议,大惊曰:“卿今者才略,非复吴下阿蒙!”蒙曰:“士别三日,即更刮目相待,大兄何见事之晚乎!”肃遂拜蒙母,结友而别。
图中①〜④表示某高等生物细胞的部分细胞器,下列有关叙述正确的是( )