Her calm face belied the turmoil she felt inside.
The simple exterior of the building belied its elaborate interior.
The exertion of climbing the stairs left him breathless.
Mental exertion can be just as tiring as physical labor.
The undulating hills stretched out as far as the eye could see.
She admired the undulating rhythm of the dance.
The children watched with mouths agape as the magician performed his trick.
She stood there with her mouth agape when she saw the breathtaking view from the mountaintop.
The puppy's ungainly attempts to climb the stairs were endearing.
He moved in an ungainly manner, not used to the bulky spacesuit.
Her quick reflexes allowed her to catch the falling glass before it hit the ground.
In a moment of danger, her reflexes kicked in, and she jumped out of the way just in time.
