"I have learned..."
A sentence starting with had would be a question: Had you seen her before that?
Yes: Which question are you speaking about? It would be found in a question.
With this question in mind, I would say yes.
Well that is a tricky question but i would say at the start of a sentence people would often use "I" at a start of sentence. There is loads of words to start a sentence so i can't tell you all of them obviously. example: "I" went to the shops to buy sweets.
No, because like when I would say "Is a boy technically a girl?", it's a question.
Well i suppose you can, but make sure i doesn't sound more like a question :)
That is not a proper question.
In English we have 'polite requests'. They are in the form of a question and start with a modal verb such as could or would or can eg Can you shut the door? Could you open the window? Would you hurry up?
The future tense of the sentence "Are you ready to learn about verbs?" would be "Will you be ready to learn about verbs?"
The future tense form of the verb "to learn" in that sentence would be "will learn." So the revised sentence is "you will learn about verbs."
"What" is often used to signal a question. An example would be, "What is the remainder when you divide 7 by 3?"
It is a declarative sentence.