Question

While I (cycle) _ throughthe park, when I (hear) a strange nioise ?

Answer 1

Jeśli to jest zdanie oznajmujące to powinno być tak:
While I was cycling through the park, I heard a strange noise.

albo tak:

I was cycling through the park, when I heard a strange noise.

Nie może być jednocześnie while i when

Answer 2

While I was cycling through the park, when I heard a strange noise.

 

a moze jednak:

 

I was cycling through the park, when I heard a strange noise.