Learn Hardcore Russian: Мама застелила деревянный стол белой скатертью и поставила на неё всю посуду. - Mom covered the wooden table with a white tablecloth and put all the dishes on it.

Russian verbs come in aspect pairs. стелить is imperfective (ongoing or habitual action), while застелить is perfective (a one-time, completed action). In this sentence Mom finished covering the table, so the perfective застелила is correct.

Why is деревянный стол in the form стол (nominative) and not стола (genitive) or another case?

деревянный стол is the direct object of застелить, so it takes the accusative case. For inanimate masculine nouns like стол, the accusative is identical to the nominative, hence деревянный стол.

Why does деревянный have two нн in its spelling?

Adjectives formed with the suffix -янн- (e.g. деревянный from дерево) always use double Н. This distinguishes them from simple adjectives with a single н.

Why is белой скатертью in the instrumental case?

The verb застелить answers the question “чем?” (with what?). You cover the table with something, so that “something” is in the instrumental. белая скатерть (nom.) → белой скатертью (instr.).

How do you decline the feminine noun скатерть in the instrumental singular?

скатерть (nom. sg.)
→ скатерти (gen. sg.)
→ скатертью (instr. sg.)
Feminine nouns ending in -ь take -ью in the instrumental.

Why is it на неё (accusative) after поставила, not на ней (prepositional)?

With verbs of placing something onto a surface (поставить на), Russian uses the accusative to indicate movement/contact. на неё shows “onto it.” By contrast, на ней (prepositional) would answer “где?” (where?) for a static location.

What does the pronoun неё refer to?

It refers back to белая скатерть. Russian pronouns agree in gender, number and case with the noun they replace. Here скатерть is feminine, so we use feminine pronoun она in the accusative: на неё.

Why is всю посуду singular and not plural (e.g. все посуды)?

посуда is a collective, uncountable noun used only in the singular. To express “all the dishes,” you say вся (posuda) in the singular. In the accusative feminine singular, вся → всю, посуда → посуду.

How does the pronoun весь change in the feminine accusative singular?

It follows regular adjective-like endings:
весь (masc. nom.)
вся (fem. nom.)
→ всю (fem. acc.)

Why are both verbs застелила and поставила in the past tense perfective?

The sentence describes two completed, sequential actions. Using perfective forms (застелила, поставила) emphasizes that each action was fully done before moving on to the next. The conjunction и simply links the two finished steps.