как

The word как is a versatile tool for beginners. Its primary functions include:

• Manner and Language: Asking how an action is performed, including the essential phrase Как это по-русски? (How/What is this in Russian?).
• State and Duration: Asking about well-being (Как дела?) or time duration using Как долго? (How long?).
• Names and Things: Used in the phrase Как тебя зовут? (What is your name?) or to ask for the name of an object: Как называется...? (What is ... called?).
• Directions and Suggestions: Essential for asking directions (Как пройти к...? - How do I get to...?), asking for repetition (Как вы сказали? or simply Как? - What did you say?), and making suggestions (Как насчёт...? - How about...?).
• Exclamations: To express emotion with adverbs, like Как красиво! (How beautiful!), or with verbs, like Как он играет! (How he plays!).
• Comparisons: Meaning 'like' or 'as' to compare things (e.g., Он плавает как рыба - He swims like a fish), as well as correlative comparisons like так же ..., как ... (just as ... as ...).
• Knowing how to / Indirect Questions: Used to express knowing how to do something or in indirect questions (e.g., Я не знаю, как это сделать - I don't know how to do this).
• Как можно + comparative: Used to express 'as ... as possible' (e.g., как можно скорее - as soon as possible).
• Role/Capacity: Meaning 'in the capacity of' or 'as a' (e.g., Я говорю это как друг - I say this as a friend).
• Verbs of Perception: Acting as a conjunction meaning 'that' or 'how' after verbs of seeing or hearing (e.g., Я видел, как он ушёл - I saw how/that he left).
• Conjunction: Functioning in specific phrases like как только (as soon as), as well as compound conjunctions like перед тем как (before), после того как (after), and the highly frequent так как (because/since). Note: While it can sometimes translate to 'when' in these fixed phrases, it is not a general substitute for когда in simple time clauses or questions.
• Fixed Phrases: Common expressions include как всегда (as always), как обычно (as usual), как ..., так и ... (both ... and ...), когда как (it depends), как сказать (how should I put it / it depends), как раз (just / exactly), как бы (as if / sort of), and с тех пор как (since).

Important Contrasts and Rules:

• Как vs. Какой: Do not confuse как with какой. Use как for adverbs or states (How beautiful!). Use какой when you are describing a noun (What a beautiful house! / Какой красивый дом!).
• Как vs. Что: When translating 'that', do not use как after verbs of thinking, knowing, or speaking (e.g., знать, думать, говорить). In these cases, что is strictly required (e.g., Я знаю, что он дома - I know that he is at home).
• Punctuation: A comma is strictly required before как whenever it introduces a subordinate clause (e.g., Я знаю, как это делать) and generally in standard comparisons (e.g., Белый, как снег - white as snow). However, a comma is strictly forbidden when как means 'in the capacity of' (e.g., Я говорю это как друг) or when the comparison functions as an adverb of manner (e.g., Он плавает как рыба - He swims like a fish).