They agreed to lend us the car on condition that we returned it before the weekend.

　　他们同意把车借给我们，条件是我们必须在周末前归还。

　　My parents don't mind what job I do as long as I am happy.

　　我的父母不在意我从事什么工作，只要我高兴就好。

　　2．only if和if only的区别

　　only if意为"只有"，置于句首时主句的主谓要用部分倒装。if only意为"但愿；要是......就好了"，引导的从句要用虚拟语气：与现在的情况相反时，从句用一般过去时；与过去的情况相反时，从句用过去完成时；与将来的情况相反时，谓语用"would/could＋动词原形"。

　　Only if he studies harder can he catch up with others.

　　他只有更加努力学习才能赶上其他人。

　　If only it would stop raining！但愿雨会停！

其他状语从句　 　　

　　[全析考法]

　　Ⅰ.单句语法填空

　　1．(2018·天津高考改编)Let's not pick these peaches until this weekend so _______ they get sweet enough to be eaten.

　　解析：that　so that "以便；为了"，在此处引导目的状语从句。

　　2．(2017·北京高考改编)________ birds use their feathers for flight, some of their feathers are for other purposes.

　　解析：Although　句意：尽管鸟类用羽毛飞行，但是它们的一些羽毛也有其他用途。由句意可知，空处引导让步状语从句，故填Although。

　　Ⅱ.单句改错

　　1．(2015·浙江高考)If I was only a child when I studied in that classroom, I will never forget it.________________

　　解析：If→Although/Though　句意：尽管在那个教室学习时我仅仅是一个孩子，但我永远忘不了它。根据句意可知，此处并不存在条件关系，而是表示让步，应将if改为although或though。

　　2．(2014·全国卷)And it is wise to have as many good friends that we can.________________

解析：that→as　as many ... as we can为固定句式，as引导比较状语从句。