单语范例（未经PONS编辑处理）
Clenching and unclenching your pelvic floor muscles may help trigger the urine flow.
www.health24.com He clenched and unclenched his fingers, feeling unnaturally stiff.
www.cnet.com He was laughing his head off, but we had to unclench his hands from the steering wheel.
thespinoff.co.nz We allow ourselves to unclench when we're home with our families, which is one of the truly wonderful advantages of human intimacy.
www.theglobeandmail.com The men unclenched their fists, put their jackets on, and walked back through the plaza.
www.vanityfair.com