Word
Зимние ботинки должны быть тёплыми и непромокаемыми.
Meaning
Winter boots should be warm and waterproof.
Part of speech
sentence
Pronunciation
Course
Lesson
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Questions & Answers about Зимние ботинки должны быть тёплыми и непромокаемыми.
What is the function of должны быть in this sentence?
It’s a modal construction combining:
- должны (plural of должен): expresses obligation (must or should)
- быть: the infinitive to be
Together должны быть means must be or should be, indicating that winter boots are required to have certain properties.
Why are тёплыми and непромокаемыми in the instrumental case?
In Russian, when a predicate adjective follows a linking verb like быть, it takes the instrumental case. Since ботинки is plural, the adjectives become plural instrumental: тёплыми and непромокаемыми.
Why are the adjectives in plural form?
Adjectives in Russian agree with the noun they modify in number, gender and case. Ботинки (boots) is a plural noun, so its predicate adjectives also appear in plural.
Could we use the adjectives in the nominative case here, like тёплые and непромокаемые?