As you slowly return to the starting position , turn your palms toward the ceiling , flex your arms and curl the dumbbells in toward your shoulders .
当慢慢回到原位置时,手掌朝上,弯曲手臂,朝肩部方向运动哑铃。
Scientists have long speculated that ocean waves could cause an ice shelf to flex and break , but this is the first time researchers have observed a tsunami having this effect .
When a knife cuts your skin , it leaves a relatively clean cut compared to paper , which will flex a little and do more microscopic damage to the skin .
During yawning , the walls of the maxillary sinuses ( located in the cheeks on each side of the nose ) flex like bellows and help with brain cooling , according to the researchers .