2. 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.

单词:
million
[ 5miljEn ]
num.百万, 百万个
n.无数

millions
n.数百万

comet
[ 5kCmit ]
n.彗星
与之相关的用法与说明:
short-period comets
短周期彗星
telescopic comet
望远镜观察到的彗星
comet of Neptune family
海（王）族彗星
comet of Saturn family
土族彗星
comet of Uranus family
天（王）族彗星
A celestial body, observed only in that part of its orbit that is relatively close to the sun, having a head consisting of a solid nucleus surrounded by a nebulous coma up to 2.4 million kilometers (1.5 million miles) in diameter and an elongated, curved vapor tail arising from the coma when sufficiently close to the sun. Comets are thought to consist chiefly of ammonia, methane, carbon dioxide, and water.

century
[ 5sentFuri, -tFEri ]
n.世纪, 百年, 百个, 板球中的一百分, 百元(钞票)

相关用法:
centuries-old
adj.
历史悠久的
in the eighties of the twentieth century
在20世纪80年代
century plant
【植】龙舌兰(世纪树)


根据这个句子联想起的单词:
million => billion
comet => sun 太阳
solar system 太阳系
Mercury 水星
Venus 金星
Earth => moon 地球 月亮
Mars =>Phobos 火星 火卫一
Deimos 火卫二
Jupiter　木星
Saturn 土星
Uranus 天王星
Neptune 海王星
Pluto 冥王星

century = > hundred