"The doctor sees the heart from inside."
Translation:Der Arzt sieht das Herz von innen.
When to use "sieht...aus" combination? I think when the subject is not specified? Is that so??
But why did we use it for the watch example: "wie sieht die Uhr von innen aus?"
Perhaps a better translation for aussehen would be "to look like", which would make the clock example "what does the clock look like from inside?".
From one DUCK to another... It probably means that the doctor (quack! Pun intended) is using a medical instrument and is able to see someone's heart inside their body.
Spot's sentence doesn't work because there has to be a verb as the second element of the sentence. Notice both of Christian's sentences have the verb 2nd as well.
Der Arzt sieht von innen das Herz.
Von innen sieht der Arzt das Herz. (very unusual)
Note that all these variants have slightly different meaning/emphasis. IMHO duo's version is best in conveying the intended meaning.