Question

which sentence uses this meaning of concrete? concrete noun a gray building material made with cement we cant walk on the sidewalk because the concrete is still drying. his fingerprints were concrete proof that he had opened the safe.

Explanation:

To determine which sentence uses "concrete" as a gray building material made with cement, we analyze each option:

• In "We can't walk on the sidewalk because the concrete is still drying," "concrete" refers to the building material (used for the sidewalk) that is drying, matching the given definition.
• In "His fingerprints were concrete proof that he had opened the safe," "concrete" is used as an adjective meaning "solid" or "definite" (not the building material), so it does not match the definition.

Answer:

We can't walk on the sidewalk because the concrete is still drying.