a.- My brother and I aren't at school.
b.- My bicycle isn't blue.
c.- The weather isn't sunny.
d.- Elisabeth isn't tall.
e.- My cousins aren't friendly.
f.- The house isn't big.
g.- I am not the best student.
h.- He isn't from Portugal.
i.- It isn't a quarter past three.
j.- The pen isn't expensive.
k.- His parents aren't doctors.
l.- The book isn't difficult.
m.- David isn't from France.
n.- The birds aren't red.
o.- It isn't ten o'clock.
p.- We aren't the champions.
q.- They aren't eleven.
r.- Lions aren't small.
s.- The computer isn't "OFF".
t.- It isn't windy today.