有个英语小问题What do you think of stress?Is it a good thing or a b

有个英语小问题
What do you think of stress?Is it a good thing or a bad thing?
Most of the students think stress can do harm to them in some ways.There’s a story about a teenager in a middle school.He even gave up his study because of the stress from school and family.We also usually hear that someone turns to psychological(心理的) doctors because of heavy working stress.There is no doubt that some people think stress is a dangerous wolf.
On the other hand,other people argue that stress is not a bad thing.They believe stress can produce momentum(动力) in the end.For them,right attitude(态度) and action can reduce stress and make it useful.When l was a child,my mom always pushed me to study hard.She wished I could go to an ideal college for further education.I experienced stress for the first time.Born to a poor family,I deeply knew life was not easy for us,and everything my mom did to me was just to hope I could live a better life in the future.As the saying goes,"No pains,no gains." So I did what my mom expected because I didn’t want to let her down.At last,I did measure up(达到标准) to my mom’s expectation and go to college successfully .Thanks to my mom’s push!Thanks to the stress!In this way,I don’t think stress is a bad thing.
Overall,stress is not a bad thing in itself.The key is how we deal with it.
“ So I did what my mom expected because I didn’t want to let her down.”这句话中（文中倒数第四行）,because为什么与so连用了?其他的三个选项有so,that,so that貌似都不对,这是为什么呢

这个so是跟上边的,并不与后面的because构成因果关系,当他们构成因果关系时,because不能与so连用