The new teacher was under heavy work pressure at that time, she

The new teacher was under heavy work pressure at that time, she could not fall asleep at night.
【正确答案】：The new teacher was under heavy work pressure at that time. She could not fall asleep at night./The new teacher was under heavy work pressure at that time,and/so she could not fall asleep at night. /Because the new teacher was under heavy work pressure at that time, she could not fall asleep at night.