在最坏情况下，堆排序需要比较的次数为 【2】 。

阅读理解。

      Do you keep pet fish at home? It is fun to keep pet fish. I have got a tank, the tank has two fish in it. one is

a goldfish, and the other is an angel fish. the angel fish has black stripes. it looks prettier than the goldfish. I feel

happy when I look at them. I usually look at them when I have something unhappy or feel tired.

      I always keep the water in the tank clean, because both the goldfish and the angel fish like clean water. They

can't live in dirty water. In winter, I need a heater in order to keep water warm. The angel fish doesn't like cold

water. I only feed the fish once a day. Too much food may make the fish die.

1. It is _______ to keep pet fish. [ ]

A. very interesting

B. easy

C. expensive

D. important

2. I have got _______ pet fish. [ ]

A. one

B. some

C. two

D. many

3. The angel fish _______ stripes. [ ]

A. has black

B. has white

C. doesn't have

D. has yellow

4. When you keep pet fish, you must _______. [ ]

A. give the fish much food

B. keep the water warm all year

C. feed them three times a day

D. keep the water in your tank clean

5. What's the meaning of the word "tank" in the first paragraph? [ ]

A. 坦克

B. 蓄水池

C. 柜子

D. 鱼缸

下图6中甲为某区域地形图、乙为该区域人口密度和人口合理承载力情况图，读图完成小题。

小题1:该区域最主要环境问题是（   ）

A．凌汛

B．水土流失

C．森林面积减少

D．泥石流频发小题2:造成这种环境问题的人为原因是（   ）

A．人口密度超过该地区合理承载力

B．A地区的人口密度高于B地区

C．人口密度在北部最为合理

D．本区人口合理承载力较大

关于文学研究的基础，朱光潜的理解不包括（）。

A.根本不知是精神上的残疾

B.知得不正确是趣味低劣

C.知得不周全是趣味狭窄

D.“知”是“行”的前提

简述我国《水法》规定的禁止性行为的规定。