题目

________ some people think advertisements bring much convenience, others are cautious about the tricks advertisements play on them. A . Unless B . Although C . While D . Where 答案：C下面是几种鸟足图，分析比较这几种生活习性不同的鸟足．（1）标有字母________的足，适于捕捉小动物；（2）标有字母________的足，适于游泳；（3）标有字母________的足，适于在树上攀援；（4）标有字母________的足，适于奔走；（5）标有字母________的足，适于在沼泽地或浅水 滩中行走．