WAEC - English Language (2001 - No. 58)
It is...........this background that we can understand the issues clearly.
for
against
with
on
Förklaring
The word "against" is the answer because the sentence suggests that understanding the issues clearly is facilitated by considering the background in a way that contrasts or opposes it. This implies that the issues are viewed in relation to the background, leading to a better understanding.