They get up very early so that they can catch the first bus.或者 They get up very early in order to catch the first bus.或者 They get up so early that they can catch the first bus.都可以,你学过哪个词组,就用哪个
They got up very early, so that they can catch the first bus.so thatph.1. 为了如此...以至于;以便They got up very early, so as to catch the first bus.so as to[英] [səʊ æz tu:][美] [soʊ æz tu]生词本简明释义为了…; 以便; 庶几乎; 庶乎