Sorry, I have to amend what I said above. Since Standard German doesn't distinguish between the simple and the progressive aspects (e.g. I do vs. I'm doing), you can normally use either translation in English - in real life, context would determine which form you have to use.
However, there are a number of verbs in English whose meaning changes when they're used in the progressive aspect. English is not my native language, but AFAIK there is a difference between "we see XY" (with our eyes) and "we're seeing XY" (we have a date with XY). The German verb "sehen" normally means "to see something with your eyes", so translating it in the simple aspect makes more sense. At least I think that's what the problem here is about.
Ich sehe kann is falsch(wrong) ... the right form for I can see is : Ich kann sehen .... keep in mind that whenever you want to use Können , you must use it at the 2nd place in your sentence & put your main verb at the last place ... sorry for broken English :) I hope it helped you :)
I don't understand why if I did the answer in present continious you take it as a mistake. We are seeing the apple.
Because it is a mistake.
We don't generally use "see" in the -ing form in English when we talk about observing something with our eyes.
Only in metaphorical uses, e.g. "I am seeing his daughter" which means "I go out on dates with his daughter".
http://ebooks.edu.gr/modules/ebook/show.php/DSDIM-B100/497/5206,23935/ (search for "stative verbs")