在用电压表测量电压时,如果不能估计出被测电压的范围 ,应该先用电压表的大量程进行试触,某次实验中 ,只知道电压不超过安全电压 ,所用电压表如图所示 ,关于试触后的操作下列说法中正确的是 ( )
A:如果示数大于 15V ,则需调换接线柱重新试触
B:如果示数大于 15V,则必须换用另一个量程更大的电压表
C:如果示数在 3V 与 15V 之间 ,则需调换接线柱重新试触
D:如果示数小于 3V,则必须换用另一个量程更小的电压表
古诗文名句默写。
①自古逢秋悲寂寥,____。 (刘禹锡《秋词》其一)
②____,应傍战场开。 (岑参《行军九日思长安故园》)
③闲云潭影日悠悠,____。 (王勃《滕王阁诗》)
④____,江月年年只相似。 (张若虚《春江花月夜》)
⑤荷风送香气, ____。 (孟浩然《夏日南亭怀辛大》)
⑥夜阑卧听风吹雨,____。 (陆游《十一月四日风雨大作》其二)
⑦____,鸟鸣山更幽。 (王籍《入若耶溪》)
⑧____,猛志固常在。 (陶渊明《读山海经十三首》其十)
⑨不知何处吹芦管,____。 (李益《夜上受降城闻笛》)
⑩渡头余落日,____。 (王维《辋川闲居赠裴秀才迪》)
⑪《观沧海》一诗中,以描绘草木来烘托大海美丽多姿的句子是____,____。
⑫《论语》十二章中,多处提及学习方法,如经常复习学过的知识便会有新的发现和体会,并可以凭此成为老师,孔子说____,____。
先通读下面的短文,掌握其大意,然后从A、B、C、D四个选项中选择可以填入空白处的最佳答案。
Everyone likes holidays,because they can do what they want to.The May Day holiday is coming.The students in1class are making the holiday plans.Here are2of them.
Li Darning,the monitor of my class,is going to have a3with his parents in the city park.He says many people would like to go to the park4May Day.He can help clean the park after5picnic.Wang Lingling always works hard.She's going to have a rest at home first and then see her grandparents.Zhao Dan6he's going to Beijing to visit the Summer Palace and the Great Wall.He thinks it'll be busy7good fun.As for me.I'm going to enjoy8too.I'm going to Qingdao to9my holiday.Qingdao is a coastal(沿海的)city.There's a lot to see and to do there.I think I can have a good time there.
What's your10for the coming May Day holiday?
75-25=____
22×40=____
210÷30=____
280÷40=____