Digging in sediments in northern China, evidence has been gathered by scientists suggesting that complex life-forms emerged much earlier than they hadpreviously thought.(正确答案是c我选了e,因为之前在曼哈顿语法书上看到说suggest不能用现在进行时,只能用一般现在时态所以排除了。然后想问一下这里不用that的原因是因为用了会冗余,还是说前后的“life form”一词没有改变所以不能用呢,因为看到曼哈顿语法书上说只有当名词改变了原来的意思才能用that否则要用them来当代词)