We don't know whether (if) it is right. 我們不知道它是否正確。
The question is whether she should do that. 問(wèn)題在于她是否應(yīng)該做那件事。
Whether it is true remains a question. 是真是假還是個(gè)問(wèn)題。
試比較:
當(dāng)if從句處在主句之后作“是否”講時(shí),引出的是賓語(yǔ)從句。例如:
I don't know if it is true. 我不知道這事是否真實(shí)。
當(dāng)if從句在主句之前作“如果”講,則引出狀語(yǔ)從句。例如:
I shall go there if I have time. 如果我有時(shí)間,我將到那兒去