Some two thousand million years ago, the mountain on the sun was raised probably because______.
A. the star moved away from the sun
B. another star happened to come near the sun
C. fhe sun and the moon raised the tides on the earth
D. a large tidal wave of a star travelled over the surface of the sun
47．答案为B 根据第二段的前两句We believe，however，that some two thousand million years ago，another star wandering through space，happened to come near our sun．Just as the sun and the moon raise tides on the earth，so this star must have raised tides on the surface of the sun...和生活常识可知潮汐是由于星球接近时造成的引力而产生，因此选B。