Bird flies freely in the air.
Meaning: This means that a bird is moving through the air without restriction or hindrance in the mixture of gases that surrounds the earth.
Choice of Words: Bird is a warm-blooded vertebrate animal that can fly. Flies means to move through the air using wings. Freely means without restriction or hindrance. In indicates the location or place where something is. Air is the mixture of gases that surrounds the earth. When you put them together, "Bird flies freely in the air" describes a situation where a warm-blooded vertebrate animal that can fly is moving through the air without restriction or hindrance in the mixture of gases that surrounds the earth.
Alternative Expressions
Related Expressions