"Pas op, de hond bijt."
Translation:Watch out, the dog bites.
Be careful = wees voorzichtig or doe voorzichtig, although there may be some overlap with pas op, which comes from oppassen.
The suggested answer: 'Watch out,...' back-translates as: 'Kijk uit,....' Would 'Pas op,...' not be more accurately translated as 'Take care,...'? One of the minor irritations with this course is that sometimes an exact translation is required, and at other times the translation is okay if it conveys the intent of the original sentence. If someone was alerting me to a biting dog, then any of the following would serve as an acceptable translation to warn me: '[Beware/ Be aware/ Be careful/ Be warned / Watch out/ Look out/ Take care/ Mind/ Be wary], the dog bites.'