moest

• Verb

  singular past indicative of moeten

• Adj

het

• Article

  the (the neuter definite article)

• Pron

raadsel

1. riddle
2. mystery

oplossen

1. to dissolve
2. to solve

de

• Article

  the (definite article, masculine and feminine singular, plural)

• Prep

cilinder

1. cylinder (geometric three-dimensional solid shape)
2. certain objects of (roughly) cylindrical shape, e.g. a top hat
3. cylinder (of an engine)

kon

singular past indicative of kunnen

openen

to open