1
- to; towards表示“至”, “向”：
aside
ashore.
1.1
- in the process of (an activity)表示“在…进行中”：
a-hunting.
1.2
- in a specified state表示“在…状态”：
aflutter.
1.3
- on表示“在…上”：
afoot.
1.4
- in表示“在…中”：
nowadays.
词源
Old English, unstressed form of ON.
- variant spelling of AD- assimilated before sc, sp, and st (as in ascend, aspire and astringent).同AD- （ad在sc,sp和st前同化为a,如ascend, aspire和astringent）。