2. Meter meter kilometer kilometer centimeter millimeter millimeter micron nanometer.

3. One end of the minimum scale (or dividing value) of the measuring range (or measuring range) is close to (or close to) the vertical unit.

4, sonar electromagnetic wave reflection laser ranging

5, centimeter meter centimeter decimeter

6、 2.5 700 0.02 1 0.035 80000000 1500

7. The scale of scale A is not close to the measured object; The 0 scale of the ruler is not aligned with one end of the measured object.

8, making geometric figure scale;

Steel tape measure-measure the length and width of the glass window;

Meter ruler cutting cloth;

Leather tape measure-measuring long jump performance.

9, 20 cm 0. 1 cm (or 1 mm) 3.50 0.035

10、C

1 1、C

12、B

13, the scale is as long as it is, and it is impossible to make a reliable judgment on things only by sensory observation (or make an accurate judgment on things with the help of tools; People's direct observation has limitations)

14, 1.3 primary and secondary schools

15、A