靈活應用代詞"it,so,that,this",使下列句子更簡練
（1）You should work harder,if you work harder ,you will make great progress.
（2）The birds sit on the backs of the elephants for food,if they don't sit on the back of the elephants ,they have to seek food in remote places.
（3）To up early in the morning and do some reading is a good habit.
（4）She was late for work because of having been caught in the traffic jam.
請認真回答,我會看情況加分的.3 Q.
注意：靈活的 “拆 分” 句子 而且只能用"it，so，that，this",