题目内容

两个同频率正弦量为同相和反相，它们之间的相位差分别为（）。

A. 0，180°
B. 90°,180°
C. 0,90°
D. 90°,0

查看答案

搜索结果不匹配？点我反馈

更多问题

正弦交流电的三要素分别是（）、（）和（）。

我国的电网频率是（）HZ.

通常胶体金质控线上为哪种物质？

A. 羊抗鼠抗体
B. 胶体金分子颗粒
C. 待检测毒物标准品
D. 选我必错

Please mark the following essay.Direction:Somepeoplethinkthattheycanlearnbetterbythemselvesthanwithateacher.Othersthinkthat itisalwaysbettertohaveateacher.Whichdoyouprefer?Usespecificreasonstodevelopyour essay. Itiscertainlysaidthatlearningisanongoingprocess.Everypersonlearnsomethingnew accordingtotheirage,experience,knowledgeandeducation.Accordingtomypointofviewitis alwaysbettertohaveteacherorguideforstudy.Oneteacherhasadequateknowledgetoteachtheirstudent.Heknowsallthepossiblewaysto makesubjecteasierforthestudents,moreover,heteachestheminaneffectivemanner.For example,somestudentsareweakinsomesubjectsbutateacheralwaysguidesthemaccordingto theirmentalcapacity.Heteachesthemasfun.Somepeoplecanlearnbetteringroupbydiscuss thetopicswithothers.Inclasspeoplecanknowtheviewsofothers,eventheyknowhowwecan learneffectively.Wheretheteacheralwaysgivesaneasydirectiontolearn. Inthetoday’scompetitiveworld,everybodyisbusy,somepeoplethinkthatrathertowastetheir timetogoforclassestheycanlearnbettertheirsubject_.TheycanattendonlineclassesbyusingtheInternetathome.TheycangetrelevantinformationfromtheInternetregardingtheirtopic. Thereisnotspecifictimeoragelimittolearnsomethingnew.Somenewthingswecanonlylearnfromexperience–forexamplenewfacts,newhabitsandsoon. Insumup,Iwouldliketosaythatitisalwaysbetterforthepeopletohaveateacherbecausea teacherhasgoodknowledge,experienceandiseducatedhowtoteachothers.Peoplewilllearn fromateacherinaneasierway

A. 7
B. 6.5
C. 5
D. 4