comet of Saturn family

例句：

1. 1.The comet was visible from the telescope for several days.
   这颗彗星在望远镜中可见数日。
2. 2. Comets are knownto be caused by collisions between gasparticles.
   已知彗星是由气体粒子的碰撞造成的。
3. 3. The discovery of a new comethas excited scientists worldwide.
   新彗星的发现让全世界的科学家都感到兴奋。