直接贴正确句子: Digging in sediments in northern China, scientists have gathered evidence suggesting that complex life-forms emerged much earlier than previously thought.
主语比较: A do sth than B do.(AB为对等名词,加do是为了显示这是一个可以发出动作的名词,因而确定是主语,进而确定是主语对比)
介宾比较: A do sth of C1 by D1 than of C2 by D2.(C1C2,D1D2对等名词)
宾语比较: A do C1 than C2.(C1C2为对等名词)
状语比较: A do sth than usual/everbefore/people expected(直接加状语)