Question

Discovery in a South African cave suggests that modern human behavior ____ much earlierthan ____.

A．begin, previously thought	B．began, previously thought
C．should begin, previous thinking	D．began, previous thinking

Answer 1

B

解析试题分析：考查时态及非谓语动词。句中的动词suggest为“表明”之意，故从句用真实语气，根据时态用一般过去时；逻辑主语modern human behavior与think为被动关系，故用过去分词，分词前只能用副词修饰。句意：在南非一个岩洞发现表明，现代人类行为的开始要比先前认为的要早的多。故B正确。
考点：考查时态及非谓语动词