20. The human brain is like a super computer, storing millions of bits of information that it can be  recalled instantly.(A)like (B)storing (C)bits (D)it

28. According to the passage, what is true of the U.S. commercial airline system? (A) It is not considered safe any more. (B) It still suffers from several problems. (C) It should treat airline personnel better. (D) It does not provide satisfactory free meals and hotel rooms.