有一读者问：有这样两句话：
(1)An Arab was walking alone through the desert ...
(2)It winds its way from west to east, across deserts, over mountains,through valleys ...
为什么在 desert(s)之前一个用 through，一个用 across?
through 和 across 皆可译作“穿过”或“越过”，用在 desert 之前。但 throught the desert 强调“穿过沙漠的范围”，across the desert 强调“横过沙漠的表面”。
