一、用单词的适当形式完成句子
1．All the (legal) constructed buildings must be pulled down. (所给词的适当形式填空)
【答案】illegally
【详解】考查副词。句意：所有违章建筑都必须拆除。空处修饰constructed，需用副词作状语，表示“违法地”应用illegally。故填illegally。
2．We have reached a stage where we must start taking (effect) measures to protect the environment so as to save ourselves. (所给词的适当形式填空)
【答案】effective
【详解】考查形容词。句意：我们已经到了必须开始采取有效措施保护环境以拯救我们自己的阶段。空格处用形容词作定语，修饰名词measures，effect的形容词是effective，意为“有效的”，故填effective。
