L1 求教关于income taxes的一点问题 revenue, account, included, liability, recognized

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notes里面定义deferred tax liability时说产生DTL有两种情况。原文是revenues are recognized in the income statement before they are included on the tax return due to temporary differences, 另一种是expenses are tax deductible before they are recognized in the income statement. 我的理解是第一种是指revenue在tax return下没有计入，但是在financial account下计入了，所以导致tax payable少于tax expense.这个不知道对不对。第二种情况没有理解很好，不是很清楚这个expense的扣税和revenue的扣税有什么区别。另外一个问题是warranty liability，就是它的carrying value在financial accounting下面也要交税是么？在tax return下tax base=0. 不是很理解liability为什么也要交税。

因为没有上课，闭门造车，水平有限，望牛人帮忙。谢谢。