Question

HELP！！！一道英语语法题，求解析ORZ

It seems as if there’ve been a lot of strong earthquakes this year. And no, it’s not a signal _____ the planet is coming apart at the seams(缝隙).
A. whether B. that
答案是B，纠结于是同位语从句还是定语从句ORZ
求大神给予充分解释，拜托了>.<

Answer 1

It seems as if there’ve been a lot of strong earthquakes this year. And no, it’s not a signal __B___ the planet is coming apart at the seams(缝隙).
A. whether B. that
这儿应该是that引导同位语从句，signal就等于后边的the planet is coming apart at the seams，两者可互换。 定语从句，先行词（引导词）要在从句中充当一定的成分，而此句中that并没有充当成分。