单选题 The newly developed vehicle had been examined very ______ before it was released in the market.

【正确答案】 C

【答案解析】[解析] 单词形态：副词 1．选项均为care的不同形式，要选择单词的恰当形式。 2．由于空格前出现了副词，B选项形容词排除。 3．空格内应填入一个修饰动词的副词，被动语态常需要副词修饰，因此C．carefully为正确选项。