fragile adj. 易碎的，脆的
例句：Glasses are fragile and must be handled with great care.
玻璃制品易碎，必須小心輕放。

fragments n．碎片，斷片，片段
例句：Carry dropped the vase on the floor and it broke into fragments.
凱麗把花瓶掉在地上，摔成了碎片。

fraction n．小部分，片斷，分數
例句：She has done only a fraction of her homework.
她只做了家庭作業的一小部分。

friction n. 摩擦，摩擦力
例句：Friction against the rock combined with the weight of the climber, caused his rope to break.
與巖石之間的摩擦加上攀登者的重量，使得繩子斷了。

fracture n. 破裂，骨折 v. （使）破碎，（使）破裂
例句：Fracture of the leg can be very serious in elders.
老年人腿骨骨折有可能成為嚴重疾患。