A
1 a fifth time和the fifth time
2 a great deal和a good deal
3 a great many——表示“许多，大量”的一些短语
4 a kind of,this kind of,many kinds of和a sort of
5 a must和a need
6 a room,many rooms和much room
7 ability,capability,capacity,talent,gift和genius
8 able,capable和competent都可以表示“有能力的”,均可作定语或表语,但有区别
9 aboard,abroad和board
10 abound with和abound in
11 absent in和absent from
12 access和excess
13 accomplish,complete和finish
14 accomplishment,achievement,attainment和success
15 account,account for和onaccount of
16 accuse和charge均可表示“指控，指责，控告”，但有区别
17 across和through
18 act,action，deed和activity
19 act as和act for
20 actual和present
21 adapt,adjust和accommodate
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