一个物体在凸透镜前30cm处,在屏上成一倒立缩小的像,则凸透镜的焦距f为( ) 发布时间:2017-05-27 21:51 │ 来源:www.tikuol.com 题型:选择题 问题: 一个物体在凸透镜前30cm处,在屏上成一倒立缩小的像,则凸透镜的焦距f为( )A.15 cm<f<30 cmB.f>15 cmC.f<15 cmD.f>30 cm
题型:选择题 根据音标拼写单词,使句子意思完整正确。1. He [spendz] _____ too much time playing with them.2. It's my first time to _____ [ju:z] the computer.3. I usually go to bed at 9:00 but I can't go to _____ [sli:p] at once.4. He is busy _____ ['pr?ktisi?] organizing the activities.5. They are good _____. ['swim?z] 查看答案
题型:选择题 男,55岁,因持续胸痛10小时收入院。查体:BP120/80mmHg,高枕卧位,双肺可闻及较多细湿啰音,啰音范围大于1/2肺野。心电图示:V1~V4导联ST段抬高0.2~0.4mV。该患者的心功能分级是:()。A.KillipⅡ级B.NYHAⅢ级C.NYHAⅣ级D.KillipⅣ级E.KillipⅢ级 查看答案