我国地形多种多样,山区面积广大.图中表示山地景观的是( ) A. B. C.

题型:选择题

问题:

我国地形多种多样,山区面积广大.图中表示山地景观的是(  )

A.

B.

C.

D.

考点:世界的地形
题型:选择题
计算:(1)(
27
+
1
3
)-(
12
-
1
5
+
45
)
(2)
4
4
5
•3
5
÷(-
3
4
10
)
题型:选择题

某筛分作业,入筛物料中小于筛孔的占60%,筛上中小于筛孔的占10%,求其筛分效率?

题型:选择题

阅读下列短文并按要求回答问题。

     In China, more and more middle school students are getting shorter sleeping time than before. Most

students sleep less than nine hours every night, because they have much homework to do. Some homework

is given by their teachers, and some by their parents. Also, some students don't know how to save time.

They are not careful enough while they do their homework, so it takes them a lot of time. Some students

spend too much time watching TV or playing computer games. They stay up (熬夜) very late. Some students

have to get up early every morning on weekdays to get to school on time by bus or by bike. It can be a long

way from home to school. It will probably make them sleepy (困的) during school hours.

     Schools and parents should cut down some of the homework so that our children can enjoy more than

nine hours of sleep every night for their health. For children, they should make the most (best use) of their

time. When they have enough time for sleeping, they will find it much better for both their study and health.

1. According to the passage, who else gives children some homework to do besides their teachers?

    (no more than 2 words)

    _____________________________________________________________________

2. How many hours of sleep is good for students' health? (no more than 4 words)

    _____________________________________________________________________

3. What is most likely to happen to a student who often goes to bed late and gets up early?

    (no more than 7 words)

    _____________________________________________________________________

题型:选择题

青霉素钠,每1IU等于

A.0.3988mg
B.0.5988μg
C.0.05988mg
D.0.3988μg
E.0.05988mg

题型:选择题

将三甘醇浓度提高到98.5%以上最常用的方法是()。

A、降低再沸炉温度

B、加入汽提气

C、增大循环量

D、提高精馏柱温度

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