英语帮忙检查有没有错误,

应该如下：
I think my cousin should go abroad to study for a degree.In this society,if you don't have an advanced degree,then you can't find a good job.Going abroad can improve your knowledge and let you see the world in a wider perspective.Thus,I suggest that my cousin go abroad to study.
During the summer,Li Hua passed by a swimming pool one day when he suddenly heard someone shouting help.He quickly turned his head to the pool and found a child drowning in the water.He immediately jumped into the poor to save the child.Finally the child was successfully saved.
I was doing my homework one day when my mom came back and said "I am tired".I anwsered "I don't think so.All you did was go to work!" Then she went to the kitchen to prepare dinner.
A few days later,my two classmates and I took part in an activity which was to work in the New China Childen's Store for one week.The first day when I worked there I didn't know what to do.But shortly aftewards,I knew what I should do and at the same time,learned that this job wasn't easy.I have to take the toys that the children likes to them.Sometimes,they'll even change their minds several times.I feel really tired when it's the end of the day.I think our parents must be more tired then we are when they are done with work.Thus,we should let them rest and help them in whatever way we can.