理解できましたか？　と問われてその解答 を英語に訳すと？

次のような表現が一般的です。日本語では「理解した」と過去形にしますが、英語では「understand」と、現在形を使います。

(1) I understand it completely.

(2) I understand most of it.

(3) I understand more than half of it.

(4) I understand about half of it.

(5) I understand some of it.

(6) I don’t understand most of it.

(7) I don’t understand any of it.