Air is an invisible and intangible object, so it does not occupy a certain space. (10) (occupied space)
3. Well water is clear and transparent, which is a kind of pure water. (x) (rich in minerals and impurities, not pure water)
There are obvious seasonal changes in every part of the earth. (×) (tropical summer all year round, cold winter all year round, rainy season and dry season in Indian Peninsula)
5. The object floating on the water is buoyed by the water, while the object sinking in the water is not buoyed by the water. (×) (All objects in the water are subject to buoyancy)
6. All animals whose bodies can be divided into head, chest and abdomen are called insects. (× )
(People seem to have a head, a chest and a belly, O(∩_∩)O~)
7. Potatoes are fruits. (×) (It's a vegetable)
8. The "white gas" released when water boils is water vapor. (×) (Water vapor is invisible gas, and "white gas" is water vapor liquefied into water droplets and scattered in the air)
9. The leaves of plants are mostly green and flat, which are divided into three parts: leaves, petioles and veins. (√ )
10. Magnets can attract all kinds of metals. (x) (If mercury cannot be attracted, it is mercury)
1 1. Friction will affect the motion of objects, so try to reduce friction at all times. (× )
(Many times we deliberately increase the friction to use, such as the brake system)
12. Environment affects the growth of plants, but plants will not affect the surrounding environment. (x) (mutual influence, such as heavy water vapor in the Woods and fresh air)
13. General objects (including solids, liquids and gases) have the characteristics of expanding when heated and contracting when cooled. (×) (This is not easy to judge, usually yes, there are exceptions, such as water, which starts to freeze when it drops to zero, not shrinking, but expanding in volume)
14. The boiling point of water is 100 degrees Celsius at any time. (x) (The boiling point will change at different temperatures and pressures)
15. Alcohol lamps should use external flames to heat objects. (√) (High external flame temperature and low internal flame temperature)
16.Bevel is also a simple machine. (√ )
17. The lever must be used with less effort. (×) (Different levers exert force, sometimes saving effort, sometimes laborious)
18. If people's production activities do not follow the ecological laws, it will destroy the ecological balance. (x) (not necessarily)
19. In most parts of China, the southeast wind blows more in summer and the northwest wind blows more in winter. (√) (reluctantly)
Food shortage is the only crisis facing the world today. (x) (not unique)
2 1. About 700,000-200,000 years ago, a group of primitive humans lived in the Gulong Cave in Zhoukoudian, western Beijing today. We call them Beijingers (√)
22. Papermaking, printing, compass and gunpowder were the four great inventions of ancient China. (√ )
23.1On June 3rd, 839, Li Zicheng collected opium in Humen and destroyed it publicly. (x) (it should be1June 3, 840)
24. The armillary sphere and seismograph were invented by Li Shizhen. (x) (Invented by Zhang Heng)
25. People's Republic of China (PRC) is located in eastern Asia, on the west coast of the Pacific Ocean. (√ )
26. Lotus root grows in water and is the root of plants. (10) (plant stem)
27. Sparrows migrate for the winter. Sparrows are migratory birds and do not migrate. Goose migration)
28. Rats and sheep are omnivores. (×) (Sheep are vegetarian)
29. Air guns are made by using the elasticity of compressed air. (√) Widely used in marine seismic survey. It uses an air gun to send high-pressure air into the water in a very short moment, forming bubbles, which expand and contract alternately in the water, causing earthquake vibration. )
30. Oxygen in the air supports combustion. (√)
3 1. Usually, draw a mark pointing north in the upper left corner of the plan. Actually, the beacon I saw is in the lower left corner, so it doesn't matter where it is. )
Chinese characters are the most widely used characters in the world. (√ )
33. The terrain of China is high in the east and low in the west, showing a ladder-like distribution. (×) (high in the west and low in the east)
34. The first unified multi-ethnic feudal country in the history of China was the Qin Dynasty. (√ )