题干

有两个阻值不同的定值电阻R1、R2,它们的电流随电压变化的I-U图线如图所示。如果R1、R2串联后的总电阻为R串,并联后的总电阻为R并,则关于R串、R并的I-U图线所在的区域,下列说法中正确的是(  )

A:R串在Ⅱ区域,R并在Ⅲ区域

B:R串在Ⅲ区域,R并在Ⅰ区域

C:R串在Ⅰ区域,R并在Ⅱ区域

D:R串在Ⅰ区域,R并在Ⅲ区域

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答案(点此获取答案解析)

D

同类题3

完形填空

    It began years ago, after Mom had been diagnosed with Alzheimer's. As her symptom 1, I often had a hard time figuring out what was real and what wasn't in her2. One day I was helping her find some pants that fitted, and she was 3 them on and looking in the mirror. Suddenly she turned and said,4 to her reflection in the mirror, “Well, I like her. She is always really nice to me.”

    It caught me so off guard. There we were doing 5 things, and suddenly she was talking about her reflection as if it were another person. How should I 6? I looked closely, as if there was going to be someone else in that mirror, saying, “Great. I am so glad she's 7to you.”

    Though still in 8 I knew there was no point bringing someone with Alzheimer's back to 9It wasn't, until later that I could 10 that the lady in the mirror was real to Mom.

    Another time I walked in, finding Mom 11 I was going to leave when Mom woke up. “Hi Mom, it's me, Molly, your daughter.” Since Mom may or may not 12 me when we meet, I always identify myself to her.

    That day she remembered me. She 13 my arm slightly and said, “Hi, honey. Come here, I want you to meet someone 14 she leaves.” And so I was reintroduced to the lady in the mirror. I 15 her as if someone were really there, and that was 16for Mom.

    I am glad she loves her17 because she sees herself as a kind being. This is yet another18 my mother has taught me: We should love ourselves and others with the kind of 19 my mom has for her lady in the mirror, even though she doesn't know she is seeing herself, my beautiful, loving, and 20 Mom.

同类题4

阅读下面的文章,完成下列小题。

少年书架

       ①喜欢书,像喜欢一件宝物。小时每每发了新书,都要找来旧报纸,包了书皮,工工整整写上:语文、数学……然后是班级姓名。手里托着书,美滋滋看着,心里有份庄重,有种没来由的稳妥。

       ②学期末,新书变旧书,一如既往的整齐,只是有了岁月的痕迹,泛着淡淡的黄。细心收起来,放到纸箱里,来年春天,再搬出来晒太阳。

       ③偶然去老师家,一进门就呆住了:老师客厅的一面墙,宽宽大大一面架子,大大小小的书,一本本直立着,是一队队意气风发的少年,春风荡漾啊!罗列其中的,还有照片,石膏雕像,或者一盆小小的文竹……我真是看呆了,书,可以这样放,多好!

       ④那是王老师用木板和木条,自己钉在墙上的,美其名曰:书架。我用手抚摸着那粗糙的木条、木板,还有书,像是久别的朋友,细腻,温暖。

       ⑤我迷恋上老师书架的样子了,在书桌前,把书一本本立起来,左右用厚厚的字典做靠背,俨然一个小书架了。这小小发明,竟然让我激动了许久。

       ⑥放学回家,喜笑颜开地告诉爸妈,我有书架了!爸妈一愣,哪里的?

       ⑦待我把在老师家里的所见,以及自己在书桌上摆放的事告诉他们的时候,妈妈嘴角漾起一份笑意,眼里还有一抹难以名状的光泽。

       ⑧那时,家里的条件不好,能上学读书,已经是很幸福的事情了,哪里还敢奢望买上一件这样“无用”的家伙呢?当然,我也会悄悄想:什么时候,我也会真的拥有一个那样的小小书架?

       ⑨那是一个秋日,天,蓝蓝的,几片厚厚的白云,暖暖地轻轻飘着。爸爸下班回家,推着自行车进了院子,朗声道:够了,够了!

       ⑩什么够了?我和妈妈惊奇地从屋子里跑出来。看,这些木头足够做一个小书架了。爸爸兴奋着。我看那些木条、木板,在爸爸的自行车后架上安静地等待着。小心脏一下子活跃起来,不知所措了,我仿佛看见了,看见了那个美丽的家伙款款而来……

       ⑪爸爸利用下班的时间,去包装厂,在丢弃的废料中,千挑万选,捡来这能用的木料。

       ⑫歇班两天的爸爸,用砂纸,一点点地打磨着那些木头,准备好锤头、钢锯、钉子、油漆……放了学的我,迫不及待地往家里跑,蹲在一边,看着爸爸在木屑中忙乎。

       ⑬天,静静的;阳光,亮亮的。院子里似乎有了道道金光,两天的时间,掰着手指头过。

       ⑭小小的书架成了!

       ⑮爸爸问我,喜欢什么颜色。我想啊,想,就调成黄色吧。爸爸涂,一遍又一遍,慢慢地,小小书架成了土黄色,是秋天叶子成熟的颜色。

       ⑯风来,漆干。抱起书架,就到桌子的一角,把书一本本放进去。那欢喜,宛如莲花的一瓣,在心里,一点点开。放书的架子,是一株亭亭玉立的稻子,安静、饱满。见到它,如见到久违的老友。

       ⑰日子深一脚浅一脚地过,它在身边,不离不弃,不恼不怒。经历各种漂泊,它伴着我,慢慢换了容颜。

       ⑱家里也拥有了大大的书架,开阔大气。而它早已泛起了油渍的光,笨拙而苍老。即使如此,它都端端正正地立在我的桌前,是我的长者,沉默不语,凝视着我,撑起我的腰身。

       ⑲如果生命能够重来,陪伴我的依然是少年书架。

(选自《做人与处世》,有改动)