Them OSCO Tai ? Sin Electric

1. We started this experiment last week.

2. They came back home at 7 o'clock in the evening.

3. We decided to send this letter yesterday.

4. To whom did you give these magazines?

5. Yesterday I met Steve in the library.

6. When was the last time you saw him? / When did you last see him? - Last Tuesday.

7. You did not learn French last year.

8. What time did you start working yesterday? - After lunch. We had little work.

9. The weather was good, and my friends and I went to the park.

10. Where were you an hour ago?

11. I met her the day before yesterday, and she told me about it.

Firstly, it is a war. Due to the proliferation of nuclear weapons on the Earth, which are able to destroy a life on the planet, the problem of war and peace has become global.
Secondly, it is the global warming as well as the environmental pollution. Every day the climate of the planet is changing more and more, reserves of fresh water are depleted, the environment is being polluted. All this is the result of human's activities, and if we continue to do this, the death of humanity within a few generations is inevitable.
Poverty, famine and homelessness are the causes of death for many years. To date, the number of people suffering from hunger and malnutrition has reached 1 billion people. It creates a serious threat to the international security.
The last thing I would like to say is about endangered species of animals and plants. Their habitats are being destroyed. This is due to global warming, logging, fire, mining. To sum up, it is necessary to make conclusions about the global problems of extinction of organisms.