从属连词if, whether引导的名词从句是由一般疑问句或选择疑问句转化而来的,变成从句后,语序由原来的倒装语序变成陈述语序。whether和if意为“是否”。Let us know whether / if you can finish the work before Friday. I don’t care whether you like the story or not.She doesn’t know whether to go to the zoo.I’m not sure whether or not he will come on time.