Of the millions who saw Haley’s comet in 1986,how many people will live long enough to see it return in the twenty-first century.
在那些于1986年目睹了哈雷彗星的千万人当中,有多少能活到21世纪再次看到它的回归呢
of the millions 在那数以百万计的人当中
who saw Haley’s comet in 1986 是who引导的定语从句,修饰前面的millions 那千百万人
live long enough to see it return
adj.enough to do sth.足够的adj.来做某事
see it return ---- see sth.do sth.