I would help you understand how you should use these words, for example, you could refer to some dictionary.
I would have told you to read some grammar modules to understand this better, but i guess this would be easier to comprehend, and retain.
I could have explained and exemplified this in a traditional way too but it would have been boring.
You should have some grammar book handy to practice the same, and analyse your answers based on your understanding from merely reading this.
I know that someone who has difficulty understanding the nuances of using this grammatically will take time to grasp this and am still wondering if this could have been explained in a better way.
I hope this helps and if not, feel free to comment and let me know that this should have been explained in some other way.