单项选择题
A double star is a star that（）.
A.has a declination equal to twice that of the Sun B.comprises two stars that appear close together C.is twice as bright as a single star D.suddenly becomes much brighter and then fades
单项选择题 A correction for augmentation is included in the Nautical Almanac corrections for（）.
单项选择题 A body can only be observed at lower transit when（）.
