腱反射
参考答案:腱反射指快速牵拉肌腱时发生的牵张反射,效应肌肉表现为一次快速收缩,造成相应肌肉的移位。
将下列句子中的汉语部分译成英语,注意使用适当的形式。
1. David Beckham is a great British . (足球运动员)
2. On school days, we often our homework. (从事,忙于)
3. Working hard is of great important, but you must do some exercise to keep fit. (同时)
4. Last weekend, we went hiking. It was tired, but we all reached the top of the mountain. (最后)
5. My sister is going to be a student at an in Pairs. (艺术学校)
如图所示,一个物体静止在倾斜的木板上,在木板的倾角逐渐增大到某一角度的过程中,物体一直静止在木板上,则下列说法正确的是
A.物体所受的支持力逐渐增大
B.物体所受的支持力与摩擦力的合力逐渐增大
C.物体所受的重力、支持力和摩擦力三个力的合力逐渐增大
D.物体所受的重力、支持力和摩擦力三个力的合力不变