We and wij are interchangeable without context, but if you had a type what you hear exercise, you should enter the word that is said by the voice.
And how do you tell the difference between "wij" and "we" when pronounced in Dutch?
Have a look at this website: http://www.heardutchhere.net/DutchPronunciation.html
I have the same question as ddaku...only my exercise was not a "type what you hear" exercise, and would like to know when to use wij vs. we. Thanks!