Hi, I have a problem with using comma in sentences and need help. There are three sentences of my writing that a teacher has revised them. He has proposed comma in all of them, and I cannot understand it these three proposed commas are obligatory or optional? And why? Would you please explain? Thanks.
- I believe this may be a boring deed[,]not an attractive pastime.
- If they miss a secure job, there is no assurance that they will find another job opportunity[,] even one similar to the missed job.
- Consequently, students waste many pleasant things because they are hard to do[,] such as attending classes.
- I believe this may be a boring deed[,]not an attractive pastime.
- If they miss a secure job, there is no assurance that they will find another job opportunity[,] even one similar to the missed job.
- Consequently, students waste many pleasant things because they are hard to do[,] such as attending classes.