Необходимо вставить предлог или наречие.

1. Laser light differs . . . ordinary light.

2. This differ¬ence results . . . the fact that this light is more intense.

3. ... means . . . some microscopes we can observe the movement of these particles.

4. This material was examined . . . new ways.

5. He is working . . . the problem of using the source of light in industry.

6. Many new instruments and devices have been built … this purpose lately.

7. This work consists . . . two parts, the first one having already been done.

1. Laser light differs from ordinary light.
Explanation: In this sentence, the preposition "from" is used to indicate that laser light is not the same as ordinary light. Laser light and ordinary light have different properties or characteristics.

2. This difference results from the fact that this light is more intense.
Explanation: In this sentence, the preposition "from" is used to show that the difference between laser light and ordinary light is caused by the fact that laser light is more intense. The intensity of the light is the reason for the difference.

3. ...means by which some microscopes we can observe the movement of these particles.
Explanation: In this sentence, the preposition "by" is used to indicate the means or method through which we can observe the movement of particles using some microscopes. The preposition "by" shows how something is done.

4. This material was examined using new ways.
Explanation: In this sentence, the preposition "using" is used to indicate the method or means by which the material was examined. The preposition "using" shows the way in which something is done or used.

5. He is working on the problem of using the source of light in industry.
Explanation: In this sentence, the preposition "on" is used to show the topic or subject of his work. He is focusing his efforts and attention on the problem of using the source of light in industry.

6. Many new instruments and devices have been built for this purpose lately.
Explanation: In this sentence, the preposition "for" is used to indicate the purpose or reason for which many new instruments and devices have been built. They were created specifically for this purpose.

7. This work consists of two parts, the first one having already been done.
Explanation: In this sentence, the preposition "of" is used to show the composition or components of the work. The work is made up of two parts, and the first part has already been completed.