用显微镜和普通天文望远镜观察物体时,你注意过像的正倒吗?如果还没注意过,请你根据已学过的光学知识判断,关于像的正倒,以下说法正确的是( )
A:用显微镜观察时像是倒立的,用天文望远镜观察时像是正立的
B:用显微镜观察时像是倒立的,用天文望远镜观察时像是倒立的
C:用显微镜观察时像是正立的,用天文望远镜观察时像是倒立的
D:用显微镜观察时像是正立的,用天文望远镜观察时像是正立的
①在聊天室中,使用网名,不用真实姓名
②不恶意制造、传播谣言
③不侮辱他人人格
④不利用网络进行诈骗活动
关于乡村聚落主要从事的工作有 ( )
根据下列句子及所给单词的首字母,在答题卷上按题号写出各单词的完全形式(每空限填一词)。⑴My grandfather likes to water the f____ in the garden on weekends.⑵The boy is too young. So don't leave him a____ at home.⑶If I don't help my mom do some h____ on weekends, my mother will be very angry with me.⑷Last night I didn't go to bed u____ the TV program was over.⑸Last Sunday I w____ a letter to my father.⑹I need to look smart for my job i____ .⑺He f____ his test last week. He should study hard.⑻He m____ his teacher in the street yesterday.⑼When the little girl saw the big tiger, she felt very s____ .⑽Last week, I p____ 500 yuan for my new bike.
一元二次方程x2﹣2x=0的解是( )