Two very common student errors are to use agree, disagree and appreciate as adjectives. They are NOT adjectives; they are verbs.
Thus, on a survey, I would ask:
Do you agree or disagree with the following statement: “English is an important language.”
You would answer:
I agree. OR I disagree.
If you want to give a longer answer, you can say: “I agree that English is an important language.”
You can NOT say “I am agree” because we don’t put two verbs next to each other in this way.
Similarly, appreciate is a verb. If you want to thank someone for his or her help, you say: “Thanks! I appreciate it.”
You can also put an object after this verb. You can add:
“Thanks! I appreciate your help. I appreciate your time. I appreciate your kindness.”
We can NOT say: “I am appreciate it” because we don’t put two verbs together in this way.
So now, to me, you can say: “Thanks for this lesson. I appreciate your grammar blog. I agree that it is very helpful.”