[解析]
(1)A.词义猜测题。根据第一段中"Have you ever noticed that the stars sometimes appear brighter in December,January and February?(你有没有注意到,星星有时在12月、1月和2月显得更亮?)"以及画线词上文"And in the summer,moisture can make stars appear more"可知,星星在冬天会显得更加亮,因此相对应的,夏天因为水分的原因星星就显得不那么闪亮了。画线词意思为"不闪亮",与not shiny同义。A.not shiny不闪亮的;B.not exciting不刺激的;C.not severe不严重的;D.not smart不聪明的。故选A.
(2)C.细节理解题。根据第二段"Air temperature is also what puts the twinkle twinkle in the little stars. "Even on very clear nights,some of the atmosphere is cooler,and some of the atmosphere is warmer," said Tumshek,who also works with the Allegheny Observatory.And when the light from a star passes through those bubbles of varying temperatures, "it bends and shifts the light,so that we are seeing stars appear to dance or twinkle," she said.(气温也是小星星一闪一闪的原因。在阿勒格尼天文台工作的Tumshek说:"即使在非常晴朗的夜晚,有些大气会更凉爽,有些大气会更温暖。当恒星发出的光穿过这些温度不同的气泡时,它会弯曲和改变光,所以我们看到的星星似乎在跳舞或闪烁")"可知,空气温度通过改变恒星发出的光的方向来影响恒星的亮度。故选C.
(3)B.细节理解题。根据最后一段中"At 8.6 light﹣years away,Sirius is relatively close to Earth and the brightest star visible in the night sky.It is also large ﹣ nearly twice as big as our sun and 20 times as bright.(天 狼星距离地球8.6光年,它相对较近,是夜空中可见的最亮的恒星。它也很大﹣﹣几乎是太阳的两倍大,亮度是太阳的20倍)"可知,小天狼星的亮度是太阳的20倍。故选B.
(4)D.目的意图题。根据第一段中"Have you ever noticed that the stars sometimes appear brighter in December,January and February?(你有没有注意到,星星有时在12月、1月和2月显得更亮?)"结合文章主要解释了为什么在冬天星星看起来更加明亮,说明了会影响星星亮度的一些因素。可推知,作者写这篇文章的目的是解释为什么星星在冬天更容易看见。故选D.