有定语从句的句子都可以拆成两句,这句话就可以写成：
Todd thought of the difficulty; with the difficulty he managed to get the amount of money he needed to start his gas station.
另外,定语从句中又有一句定语从句he needed to start his gas station修饰the amount of money,由于that 所代表的名词在定语从句中作needed的宾语所以省略了.