C
　　concentrate v.全神贯注，精神集中，专心致志;集中，集合;浓缩
　　We should concentrate all our efforts on improving education.我们应该集中精力努力改进教育工作。
　　Troops are concentrating south of the river.军队正向河的南边集结。
　　n.浓缩液
　　【用法】concentrate(sth.)on sth./doing sth.
　　【全真考题】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.继续不断的;一再重复的
　　continual rain 不停的雨
　　【辨析】continual与continuous
　　continual一般指多次重复的动作：Please stop your continual questions.
　　continuous表示动作或物体继续不停地或不间断地进行下去：a continuous flow of traffic
　　【全真考题】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.(在性质、倾向或方向等方面)相反的;好与人作对的
　　contrary beliefs 截然相反的信仰
　　He is an awkward，contrary child.他是个又麻烦又不听话的孩子。
　　n.反面
　　【用法】contrary to 违反：be contrary to the law;on the contrary 与此相反：It doesn't seem ugly to me;on the contrary，I think it's rather beautiful.
　　【全真考题】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