C
　　concentrate v.全神貫注，精神集中，專心致志;集中，集合;濃縮
　　We should concentrate all our efforts on improving education.我們應該集中精力努力改進教育工作。
　　Troops are concentrating south of the river.軍隊正向河的南邊集結。
　　n.濃縮液
　　【用法】concentrate(sth.)on sth./doing sth.
　　【全真考題】Anne couldn't concentrate what she was doing while her family were watching TV.(93.1)
　　A.to B.on C.for D.in
　　【答案】B

　　continual adj.繼續不斷的;一再重復的
　　continual rain 不停的雨
　　【辨析】continual與continuous
　　continual一般指多次重復的動作：Please stop your continual questions.
　　continuous表示動作或物體繼續不停地或不間斷地進行下去：a continuous flow of traffic
　　【全真考題】Our journey was slow because the train stopped at different villages.(99.1)
　　A.unceasingly B.gradually
　　C.continuously D.continually
　　【答案】D

　　contrary adj.(在性質、傾向或方向等方面)相反的;好與人作對的
　　contrary beliefs 截然相反的信仰
　　He is an awkward，contrary child.他是個又麻煩又不聽話的孩子。
　　n.反面
　　【用法】contrary to 違反：be contrary to the law;on the contrary 與此相反：It doesn't seem ugly to me;on the contrary，I think it's rather beautiful.
　　【全真考題】What you have done is the doctor's orders.(90.1)
　　A.attached to B.responsible to
　　C.resistant to D.contrary to
　　【答案】D