题目

This is the twins' bedroom. This bed is Lily's and that one is Lucy's. The two beds look the same. The twins have one desk and two chairs. Their clock, books and pencil boxes are on the desk. Their bags are behind the chairs. Some nice flowers are on the desk, and some nice pictures are on the wall. Is there a kite? Yes, it's under Lily's bed. The bed­room is very nice.【1】The twins________．A. are in the same roomB. are in different roomsC. have two roomsD. are at school【2】We can see ________ in the room.A. a ball B. a dogC. only one bed D. two beds【3】The clock is________．A. be（16分）串列静电加速器是加速质子、重离子进行核物理基础研究以及核技术应用研究的设备，图是其构造示意图。S是产生负离子的装置，称为离子源；中间部分N为充有氮气的管道，通过高压装置H使其对地有V的高压。现将氢气通人离子源S，S的作用是使氢分子变为氢原子，并使氢原子粘附上一个电子，成为带有一个电子电量的氢负离子。氢负离子（其初速度为0)在静电场的作用下，形成高速运动的氢负离子束流，氢负离子束射入管道N后将与氮气分子发生相互作用，这种作用可使大部分的氢负离子失去粘附在它们上面的多余的电子而成为氢原子，又可能进一步剥离掉氢原子的电子使它成为质子。已知氮气与带电粒子的相互作用不会改变粒子的速度。质子在电场的作用下由N飞向串列静电加速器的终端靶子T。试在考虑相对论效应的情况下，求质子到达T时的速度。电子电荷量C，质子的静止质量 kg。