"请写在黑板上。"

Translation: Please write it on the blackboard.

[Amizore]

I feel like chalkboard should be accepted as well, since it is technically a blackboard.

[MarilynBow4]

I gave that answer and it marked me as Wrong

[prabhavati]

Shouldn't please write this on the black board be accepted

[RemieSmith]

How is the word "it" implied here? I don't understand

[Hsn626796]

You're writing something after all..

Whether words or a drawing or scribblings..

So it's an "it"

[Hsn626796]

Why both 在 and 上 ?

Just a chinesy structure thing or...
Does one not suffice the meaning without the other ?

[.Alex_]

yeah you can only use one without another

[ArthurMcDo3]

My answer seems to be correct, isn't it

[Judith903150]

"Please write it on the board" should be accepted. This is probably the most common way this request is made, especially since white boards are very prevalent now. American English speakers rarely specify the color of the board, unless they have a specific reason to.

[ChromateX]

Experimenting with other colours (might be useful, maybe give it a try), and a "blue board" 篮板 would be a backboard?