factor (sth.) in
When housing and other living costs are factor in, a month salary ¥15，000 in Beijing & Shanghai dose not seem that handsome.
Once you factor in specific circumstances, you will appreciate how heroic the pilot's action is.(something太长可后置)
作业：
1. Experienced writers would factor in the purpose and aim readers of the writing.
2. Once you want study abroad, you should factor in all possible situations.
