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.