Frik: Do you know that guy?
Frak: I _
Frik: Do you know that guy?
Frak: I __ his face, but don't __ whom he is.
Choices
remember
recognize
realize
日本語訳
フリック:あの人、知ってる?
フラック:顔は見覚えがあるけど、誰だったか思い出せない。
「I __ his face, but don't __ whom he is.」の空欄に remember/recognize/realize から選んで入れてください。
解答・解説
The answers 'recognize' and 'remember' are interchangeable. You can use them in either space; 'realize' is not an option: This is the best arrangement:I recognize his face, but don't remember whom he is.
Causal expression of this statement would be:
I recognize him, but don't remember who he is.
Or:
I recognize him, but don't remember him.
To recognize is to know someone by his or her face or other features.
To remember someone is to know his or her name (Generally. Some English speakers will argue with this distinction, but I think it is a convenient and accurate one).

I recognize his face, but don't remember whom he is. が原文の推奨する組み合わせです。「顔には見覚えがあるけれど、誰なのか思い出せない」という意味になります。recognize と remember は文脈によって入れ替えられますが、realize はこの空欄には適しません。
くだけた言い方なら I recognize him, but don't remember who he is. と言えます。原文では recognize を顔などから相手に見覚えがあること、remember を名前などを思い出すこととして説明しています。ただし、これは絶対的な区別ではありません。