What is the main idea of the passage?

Shared flag codes helped ships communicate across distance and language before radio, though visibility limited them. (The passage follows flag signaling from separate codes toward shared systems and closes by naming fog and darkness as limits.)

Why did crews need the same codebook?

Shared definitions let both crews interpret a pattern in the same way. (The passage notes that a pattern could mean nothing to a crew using a different code, so common definitions were essential.)

What are “fleets” in the second paragraph?

Groups of ships (The sentence pairs fleets with trading groups that used their own systems, indicating organized groups of ships.)

What could make signal flags difficult to see?

Fog and darkness (The final paragraph identifies fog and darkness as conditions that hid or obscured flags.)

When Ships Read Flags: Level 1 Reading Comprehension Questions

Before radio, ships could send messages with flags. Bright colors and bold shapes were visible across water. A sailor raised one flag or a group of flags, and another crew used a codebook to read the signal.

At first, fleets and trading groups used different codes. A pattern understood by one crew might mean nothing to another. During the nineteenth century, published systems helped more ships share fixed meanings. Later international codes made communication across languages easier. Some signals stood for letters, while others carried a whole message about a ship's needs or actions.

Flags still had limits. Fog could hide them, darkness made them hard to see, and each crew needed the same code. Yet in clear daylight, a few pieces of cloth turned distance into a readable space between strangers at sea.

Comprehension questions