1. It must be pointed out that, while improving the quality of the population, controlling population growth is one of the basic policies of the country.
2. It is estimated that the world's population will reach 6 billion by the end of this century.
Three. It must be remembered that the secret of success is hard work.
4. Thus, there are no difficulties in the world that we cannot overcome.
5. It is well known that man is the product of labour.
6. As the saying goes, people with fixed goals will succeed.
7. Obviously, the enemy has no desire for peace.
8. It's hard to imagine how Edison worked 20 hours a day.
9. It is difficult to say whether the plan is feasible.
10. There is no doubt that if you have difficulties, others will help you.
11. It seems that they have done a series of experiments.
12. It is said that bats have been using radar for millions of years.
13. To be honest, many of our mistakes could have been avoided.
14. We know that this problem has not been solved until recently.
15. Admittedly, you didn't do what you promised.
16. In my opinion, this computer is different from what you see.
17. We certainly have a long way to go.
18. All this shows that nothing can prevent us from achieving our goals.
19. As far as we know, it took him more than a year to finish the book.
20. It has been proved that every substance, whatever it is, is made up of atoms.