Learn Russian: Каждую неделю мы срываем яблоки с этого дерева. - Every week we pick apples from this tree.

The preposition с (used here with the Genitive case) is the direct counterpart to на. Because apples grow on a tree (на дереве), taking them off or from the surface of the tree requires с. If you were taking them out of a box (в коробке), you would use из.

Is it a coincidence that the verb starts with с- (срываем) and the preposition is also с?

Not at all! The verbal prefix с- often indicates removal, detachment, or downward movement. It is very common in Russian to pair a prefixed verb with its matching preposition to clearly reinforce the direction of the action.

Why doesn't the time phrase каждую неделю (every week) use a preposition?

When you express frequency using the word "every" (каждый), Russian uses the Accusative case directly without any preposition. Since неделя (week) is a feminine noun, both the adjective and the noun take the feminine Accusative endings (-ую and -ю).

Why do we use the imperfective verb срываем?