Breakdown of Onko sähköauto tehokkaampi kuin tämä auto?
tämä
this
olla
to be
auto
car
kuin
than / like / as (also in "before …")
Questions & Answers about Onko sähköauto tehokkaampi kuin tämä auto?
Do we need to change the case of the words after kuin?
No, when you use kuin (than), the things being compared usually stay in the same case. Here, both sähköauto and tämä auto are in the basic nominative case because they are being directly compared to each other.
The dictionary word for "powerful" is tehokas. Why does it become tehokkaampi here?
To make a word comparative (like adding "-er" or "more" in English), you attach -mpi to its vowel stem. For words ending in -kas, like tehokas, the stem is formed by dropping the -s and doubling the last vowel to make tehokkaa-. Then you just add -mpi to get tehokkaampi.
Remind me, why does this sentence start with Onko?
Onko is the verb on (is) combined with the question particle -ko. In Finnish, to ask a yes/no question, you attach -ko or -kö to the main verb and move that word to the very beginning of the sentence.
How is the word sähköauto formed?
It is a compound word made by joining sähkö (electricity) and auto (car). Finnish frequently creates new words by sticking two basic words together without any spaces.