"The man singing is not that short."
Translation:노래하는 남자는 키가 그리 안 작아요.
It got marked right for me. They say it both ways in Japanese too. If anything it would depend on whether you're comparing two people/animals's heights (키가 그리) or a person/animal's height with the height of something else (그리 키가). Whether anyone actually notices this and can articulate it is another thing . . .
Hi, since no one else has replied to you yet I thought I would even though I might not be much help. 별로 I think means "not really" 그리 means "so" in the sense of "so much" or "that" as in "that much" (like "not that short" in this example 거의 I think means "almost" or "nearly" Since you wrote your comment a month ago, I hope you are feeling less frustrated! How's the rest of the course going for you? :)
-는 is used two different ways here. The first -는 is the modifying ending used to turn present tense verbs and 있다/없다 into adjectives. Therefore 노래하다 (to sing) + 는 (modifying ending) = 노래하는 (singing). The second -는 is the topic particle -는 indicating that the man is the subject of the sentence.