TASK DEFINITION: Given a sentence, fill out the missing word with a 'no' or a number (between zero and ten). You should write the numbers with english alphabet, like: four instead of 4.
PROBLEM: Theobroma oil can exist in four different polymorphic forms of which only ____ is stable.

SOLUTION: one

PROBLEM: Niobium occurs primarily in ____ minerals, columbite and pyrochlore.

SOLUTION: two

PROBLEM: All imaginary numbers are complex numbers with ____ for the real part.

SOLUTION:
zero