【单选题】Formation flight is more comfortable because passengers can not see the other planes.
【简答题】A.Because there planes fly higher than at the equator. B.Because there the eyes can reach about 4,000 metres. C.Because there planes are clear of bad weather. D.Because there planes fly more quickly t...
【单选题】Formation flight is more comfortable because passengers can not see the other planes.
【单选题】there is ( )words in this passenge.
【单选题】A camera lens is preferable to a pinhole because it can ______ .
A.
offer a choice of planes of focus
B.
gather more light rays
C.
control the size of the image formed on the film
D.
gather more light rays and bring them to a focus at a given plane