Why do pumice stone float on the surface of the water?
A: They are
comparatively smaller.
B: They contain special
materials.
C: They are not real stones.
D: There are pores in the stone.
A: They are
comparatively smaller.
B: They contain special
materials.
C: They are not real stones.
D: There are pores in the stone.
D
举一反三
- The reason why lotus leaves do not touch water is that the upper surface of lotus leaves is covered with many papillae which are smaller than rain water.
- How did “columnar joints” come into being? A: The magma condensed into stone columns. B: The pumice stones piles layer by layer. C: The volcanoes look like columnar joints. D: Creatures were gradually fossilized and they slowly turned into a thick limestone layer on the seabed
- Why did the Egyptians build the stone pyramids ?
- “Stone<br/>carving of a horse treading on a Hun” is the masterpiece of<br/>bronzes in the () Dynasty. A: Qin B: Zhou C: Han D: Northern
- You’ll<br/>trip ______ a stone if you don’t mind out.
内容
- 0
Building materials may be classified into three groups according to the purposes they are used for: structural materials, decoration materials and some special materials.
- 1
Running in the rain, ______. A: I fell over a stone B: a stone blocked me C: a stone caused me to fall D: I was fallen over a stone
- 2
My house is within ______ from the railway station. A: a stone's throw B: a throw of a stone C: stone's throw D: the stone's throw
- 3
The<br/>safety coefficient of the capacity of composite materials is usually<br/>____ times of metal materials. A: 0.8-0.9 B: 1.0-1.25 C: 1.15-1.2 D: 1.5-2.0
- 4
They found the () bridge when they went across the village. A: old stone Chinese B: Chinese old stone C: old Chinese stone D: Chinese stone old