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.

[Q]: Acoustic instruments consist of ____ main parts neck, top, back and sides.
[A]: four


[Q]: Inhibited desire is the most common sexual dysfunction, effecting ____ in three couples.
[A]: one


[Q]: Caffeine enhances the effectiveness of the other ____ drugs.
[A]:
two