1. It must be pointed out that it is one of our basic State policies to control pulation growth while raising the quality of the population. n$z+g>~N
2. It is (has been) estimated that the world's population could reach 6 billion by the end of the century. f 3t&Bcw$
3. It must be kept in mind that there is no secret of success but hard work. @GrQ/F7
4. It can be seen from this that there is no difficulty in the world we can overcome. ;(1Xb
5. As is known man is the product of labour. SuuLB6{u3
6. It is a common saying that man who has a settled purpose will surely succeed. 6Rcl HU
7. It is clear that the enemy has no desire for peace. f:_mr zz
8. It is hard to imagine how Edison managed to work twenty hours each day. z&x3":@u<
9. It's hard to say whether the plan is practicable.
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10. There is no doubt that you will be helped by others if you have any difficulties. G:k]tZ*`
11. It seems certain that they have made a series of experiments. $~s|%>@
12. It is said that bats have been using radar for millions of years. !da[#zK
13. To tell the truth , many mistakes we made could have been avoided. _t'S<jTI
14. As we know, it was not until recently that the problem was solved. %D9,Femt
15. It must be admitted that you haven't done what you promised to do. ln~;Osb
16. In my opinion, this computer is different from that one you saw. Iq%f*Zm<
17. It is certain that we have a long way to go. F{;{o^Pv
18. All this shows that nothing can prevent us from reaching our aims. l%^VBv>
2
19. As far as we know, it took him more than a year to write the book. C[0*>W8o
20. It has been proved that every substance, no matter what it is, is made up of atoms. ~8#Ku,vEy
21. It has been decided that we are going to build a railway whose base must be completed within this year. t<