判断对错．

30□560≈31万，“□”里最小可以填4．

有学者认为，徽商胡雪岩“垄断蚕丝，冀获暴利。此既为出口大宗，适光绪九年（1883年）外国丝市不振，洋商不购，而胡氏存货山积，悉归腐敝。由是尽丧其资，波及全国，钱庄分设各地者，纷纷倒闭，而胡氏一蹶不振”。在该学者看来，胡雪岩破产的主要原因是（    ）

研究人员随机调查统计了某地1000名“上班族”每天在工作之余使用手机上网的时间，并将其绘制为如图所示的频率分布直方图．若同一组数据用该区间的中点值作代表，则可估计该地“上班族”每天在工作之余使用手机上网的平均时间是（  ）

如图是长江水系示意图，读图，完成下列各题。

读短文，判断对错。
    My name's Alice. Look at my classroom. It's big and clean. The floor is green, the walls are white. The door is yellow and the windows are blue. Two pictures are on the wall. They are beautiful. How many lights are there? Nine! My desk is near the door. My schoolbag is on the desk. What's in my schoolbag? A pencil box, an English book, a maths book, a Chinese book, three storybooks and five notebooks. I like my classroom. I like my schoolbag too.