Questions & Answers about Onko myrkky aina myrkyllistä?
Why is myrkyllistä in the partitive case here instead of the nominative myrkyllinen?
Because the subject of the sentence, myrkky (poison), is a mass noun, meaning an uncountable substance. In Finnish, when you describe a mass noun or an abstract concept using the verb olla (to be), the describing adjective must be in the partitive case.
If myrkyllistä is partitive because it describes a mass noun, why isn't the subject myrkky also in the partitive?
In a standard description sentence like this, the subject is usually in the basic nominative case when we are talking about the substance as a whole or as a general concept. The partitive rule for mass nouns here only applies to the adjective describing it.
How are the words myrkky and myrkyllistä related?
Myrkyllinen (toxic) is an adjective formed from the noun myrkky (poison) by adding the common suffix -llinen. Notice the consonant gradation: the double kk in myrkky weakens to a single k in myrkyllinen because the suffix closes the syllable. Its partitive form is myrkyllistä.
Could the question particle -ko be attached to a different word here?