Answer:Please see explanation for answers.
Step-by-step explanation:
1.Our parents were richer before they had my brother and me.
used
Our parents ………used to be richer.....before they had my brother and me.
2 I shouldn't have stayed up so late last night surfing the net.
regret
I ……regret staying ………… so late last night surfing the net.
3 I have never seen a pizza as big as that.
biggest
That's the.......... biggest i have ever ……………… seen.
4 You should have finished those letters ages ago!
been
Those letters …should have been finished ……ages ago.
5 I know it's snowing, but we should still go for our walk.
spite
We should still go for our walk, ……spite the …… snow