挡: 挡Ⅰ动词1.(拦住; 抵挡) keep off; ward off; block; resist 短语和例子挡道 block the road; get in the way; 挡风 shelter sth. from [keep out] the wind; 挡雨 keep off the rain; shelter one from the rain; 筑一道篱笆挡狗
重力: [力学] gravity; force of gravity; gravity force; power of gravity; pull of gravity; gravitational force 短语和例子这块石头由于重力作用而滚下山。 the stone rolled down the mountain by gravity.; 重力测定 gravimetric(
