Put the verb in the brackets into the appropriate form of infinitive. pay attention to the passive and active voice and using of to. state the function of the infinitive:
1. i was glad … to this meeting by my colleague (to invite).
2. my dream is … home as soon as possible (to return).
3. this student was the first …by our professor (to examine).
4. russia and the united states are carrying out the projects … and … the environmental systems of the ecologically poor regions (to study, to protect).
5. the teacher made students … two articles (to translate).
6. do you know anybody … this project already? (to finish)
7. i am glad … with him now (to speak).
8. … life on the planet is one of the main mankind’s tasks (to save).
9. nowadays the heat cannot … into space (to go).
10. it was very pleasant … with my friends again (to travel).

1. I was glad to be invited to this meeting by my colleague. (Function: to show purpose or reason for the action of being invited)
Explanation: The verb "invite" is in the past tense, so the appropriate form of the infinitive is "to be invited".

2. My dream is to return home as soon as possible. (Function: to express the purpose or intention of the dream)
Explanation: The verb "return" is in the infinitive form, so it remains unchanged.

3. This student was the first to be examined by our professor. (Function: to show the purpose or action of being examined)
Explanation: The verb "examine" is in the past tense, so the appropriate form of the infinitive is "to be examined".

4. Russia and the United States are carrying out the projects to study and protect the environmental systems of the ecologically poor regions. (Functions: to express the purpose of studying and protecting)
Explanation: The verbs "study" and "protect" are in the infinitive form, so they remain unchanged.

5. The teacher made students translate two articles. (Function: to show the action or task assigned to the students)
Explanation: The verb "translate" is in the infinitive form, so it remains unchanged.

6. Do you know anybody who has already finished this project? (Function: to show completion of the project)
Explanation: The verb "finish" is in the infinitive form, so it remains unchanged.

7. I am glad to speak with him now. (Function: to express the intention or action of speaking with him)
Explanation: The verb "speak" is in the infinitive form, so it remains unchanged.

8. Saving life on the planet is one of mankind's main tasks. (Function: to express the purpose or action of saving)
Explanation: The verb "save" is in the infinitive form, so it remains unchanged.

9. Nowadays, the heat cannot go into space. (Function: to express the action or ability of heat)
Explanation: The verb "go" is in the infinitive form, so it remains unchanged.

10. It was very pleasant to travel with my friends again. (Function: to express the action or experience of traveling)
Explanation: The verb "travel" is in the infinitive form, so it remains unchanged.