31) It remains unknown whether there are intelligent beings outside the solar system.
32) It has been pointed out that in 6000B. C. the fastest transportation available to man over.
33) It is now thought that the more work we give our brains, the more w** able to do.
34) It can be argued that such a response may not mean much (有人认为……)
35) It is reported that the electronic industry is going on rapidly in recent year.
36) It is reported that there has been a decrease in the annual birth rate over the last two decades.
37) It is estimated that the total expenses in the trial manufacture of the new products will come to 30,000 yuan.
38) Once it was thought that nighttime dreams interfered with our needed rest.
39) It has been observed that unemployment brings enormous psychological troubles.
40) Even so, it seemed to him that he was part of the whole event.
