What is the suitable response to the greeting, 'Hi.'? (It is Hello.) That's right. If your friend says, 'How is it going?', what do you have to say? (We can say, 'So-so.') What is the suitable response to the statement,'Glad to meet you.'?

(It is 'Glad to meet you,too.)
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Are the expresions above OK?

Can we use both question and statement?
ex) What is the suitable response to the question/statement, 'How are you?'

A good answer to How are you? is "Fine, thank you." or I'm well, thank you. How are you?"

Or if you want to be very informal, "Super, How are you doing?"

Thank you. I'd like to know whether my explanation is grammatical or not.

Yes, you are fine grammatically.

Yes, the expressions you provided are suitable responses in those specific situations.

When someone says "Glad to meet you," the suitable response is indeed "Glad to meet you too." It is a polite way to acknowledge their statement and express your own pleasure in meeting them.

As for your second question, you can use both the terms "question" and "statement" when referring to different types of greetings or expressions. For example, you can ask, "What is the suitable response to the question 'How are you?'" or "What is the suitable response to the statement 'Glad to meet you?'" This distinction helps clarify the type of greeting or expression being used.