48---B 49---E 50---C 51----D
52. stones and sand
53. -5C'
54. in 2005
55.20 million years
56.because they want to know how climate has changed over time and want to find the clue how .......到完。
48---B 49---E 50---C 51----D
52. stones and sand
53. -5C'
54. in 2005
55.20 million years
56.because they want to know how climate has changed over time and want to find the clue how .......到完。