46.The loss of biodiversity has a serious _______ on the survival of wildlife and humans.                                                A. affect                        B. problem                    C. impact      D. influential 47.Global warming can _______ the ecological balance, bringing about terrible consequences.                                                A. destroy                     B. upset                         C. converse  D. injure 48.Gavin _______ the idea of dividing the rooms in half.                                                A. came up with            B. work out                   C. used up    D. run out 49.We have to allow _______ the possibility that we might not finish on schedule.                                                A. to                              B. at                              C. for           D. on 50.Fourteen manufacturers were included _______ the primary development of the new aircraft.                                                A. for                            B. in                              C. at  D. about