If you treble the distance, the gravitational attraction gets nine times weaker.如将距离增大两倍, 则其万有引力就减小九分之八.Many asteroids are weakly bound piles of rubble, held together by their own minute gravitational attraction.大多数的小行星都...
...a path which suddenly dips down into a tunnel.突然下降进入一条隧道的小路At that point the road dips into a valley.在那一点那条路直向山谷伸展。Maybe we could just buy some dips.或许我们可以只买一点儿蘸酱。She flicked through a romantic paperback between occas...