题目

如图所示，a、b是两个带有同种电荷的小球，用绝缘细线悬挂于同一点，两球静止时，它们距水平地面的高度相等，绳与竖直方向的夹角分别为α、β.若同时剪断两根细线，空气阻力不计，两球带电量不变，则     ( )． A．两球a、b同时落地             B．球a先落地 C．球a水平飞行的距离比b球大    D．两球a、b水平飞行的距离相等阅读下面短文，按照句子结构的语法性和上下文连贯的要求，在空格处填入一个适当的词或使用括号中词语的正确形式填空。Every child has his own dream.Every child hopes to be 【1】 adult.However，is it really like what they imagine? As a boy【2】lives in modern times and in a modern city，I feel greater pressure(压力)on me with the 【3】(city) development.Although we seldom worry 【4】money，we still have some other 【5】(problem)，such as competition among classmates and expectation(期望)from parents.These experiences are very helpful to our future.But in fact they really give 【6】(I)a lot of pressure.I still clearly remember the happiness of my childhood.Unluckily，we have to face the fact with time passing by.We begin 【7】(feel)this invisible(无形的)pressure come upon us.We get up before sunrise 【8】 come back after sunset.We work and study like an adult，even 【9】(hard)．What we do is to get an excellent mark.Growing up is very boring，but we should try to find happiness while growing up.I think friendship among our friends，the support from our parents and the encouragement from our teachers can help us.Why not 【10】(enjoy)the pleasure of growing up and its delicious taste?