single block的用法和樣例：
例句
- A light tackle having double or single blocks, used to hoist or tighten rigging.
輕型滑車雙滑輪或單滑輪輕型滑車，用於升起或拉緊支撐船桅和帆的全部繩索 - The organizations were formed because of people's belief that the city is just too large to care about any single block.
人們認為這個城市太大難以管理到每一條街道，所以成立了這樣的組織。
