181. through, across　　

through穿越空间；例：through the forest
across在…上穿过 例：across the desert

182. on the way, in the way　　

on the way在前往…的路上；
in the way挡路 例：The chair is in the way.

183. above, on, over　　

above在上面，不接触；
on在上面，接触；
over在正上方 例：fly over the hill

184. until, not…until　　

until到…为止；例：I waited until 3:00.
not…until直到…才（常跟点动词连用）例：He didn't come until 3:00.

185. besides, except, except for　　

besides除了…还（包括在内）；
except除了（不包括在内）；
except for整体…除了某一点以外 例：The composition is good except for a few spelling mistakes.