题干

下列各组物理量中,全部是矢量的是(  )

A:位移、时间、速度、加速度

B:质量、路程、速度、平均速度

C:速度、平均速度、位移、加速度

D:位移、路程、时间、加速度

上一题 下一题 0.0难度 选择题 更新时间:2016-09-12 02:02:36

答案(点此获取答案解析)

C

同类题2

              为中华之崛(jué)起而读书
     12岁那年,周恩来离开家乡,来到了东北。当时的东北,是帝国主义列强在华争夺的焦点。他在沈阳下了车,前来接他的伯父指着一片繁华热闹的地方,对他说:“没事可不要到那个地方去玩啊!”
   “为什么?”周恩来不解地问。
   “那是外国的租界地,惹出麻烦来可就糟了,没处说理去!”
   “那又是为什么呢?”周恩来打破砂锅问到底。
   “为什么?中华不振啊!”伯父叹了口气,没有再说什么。
不久,周恩来进了东关模范学校读书。他始终忘不了大伯接他时说的话,经常想:“租界地是什么样的?为什么中国人不能去那,而外国人却可以住在那里?这不是中国的土地吗?……”一连串的问题使周恩来迷惑不解,好奇心驱使着他,一定要去看个究竟。
一个风和日丽的星期天,周恩来背着大伯,约了一个要好的同学闯进了租界地。嘿!这一带果真和别处大不相同:一条条街道灯红酒绿,热闹非凡。街道两旁行走的大多是黄头发的、白皮肤、大鼻子的外国人和耀武扬威的巡警。
      正当周恩来和同学左顾右盼时,忽然发现巡警局门前围着一群人,正大声吵嚷着什么。他们急忙奔了过去,只见人群中有个衣衫褴褛的妇女正在一旁哭诉着什么,一个大个子洋人则得意洋洋的站在一旁。一问才知道,这个妇女的亲人被洋人的汽车轧死了,她原指望中国的巡警局能替她撑腰,惩处这个洋人。谁知中国巡警不但不惩处肇事的洋人,反而把她训斥了一顿。围观的中国人都紧握着拳头。但是,在外国的租界地里,谁又敢怎么样呢?只能劝劝那个不幸的妇女。这时,周恩来才真正体会到伯父说的“中华不振”的含义。
      从租界地回来后,同学们常常看到周恩来一个人在沉思,谁也不知道他究竟在想什么。直到在一次修身课上,听了周恩来的发言才解开了这个谜。
那天修身课上,魏校长向同学们提出了一个问题:“请问诸生为什么读书?”
      同学们踊跃回答,有的说:“为做官而读书”,也有的说:“为挣钱而读书”,“为明理而读书”……周恩来一直静静的坐在那里,没有抢着发言。魏校长注意到了,打手势让大家静下来,点名让他回答。周恩来站了起来,清晰而坚定地回答:“为中华之崛起而读书!”
       魏校长听了为之一振!他怎么也没想到,一个十二三岁的孩子,竟有如此的抱负和胸怀!他睁大眼睛又追问了一句;“你再说一遍,为什么而读书?”
    “为中华之崛起而读书!”
       周恩来铿锵有力的话语,博得了魏校长的喝彩;“好啊!为中华之崛起!有志者当效周生啊!”
       是的,少年周恩来在那时就已经认识到,中国人要想不受到帝国主义的欺凌,就要振兴中华。读书,就要以此为目标。

同类题5

任务型阅读

Ways to say “Happy birthday to me”

    Tomorrow is my birthday, and I'm at an age when not everyone looks forward to cakes and presents.____It always makes me feel excited to be alive and grateful for my life and my family. So I think even if your birthday is a regular old day at work or home, there are some easy ways to raise it to the special occasion.

    Give a gift to someone else.____While everyone loves to open a birthday present, there is a lot of joy and goodness to be gained from being generous with others. Making a birthday donation(捐赠)to a charity that means something to you.____.

    Try something new. Today is new to us. Why not enjoy the newness of the moment? Dip your tones into some new waters, sign up for an adult education class, go for a new-to-you park or plan a new trip.____

    ____Whether or not you have the opportunity to share a meal, outing or party with friends and family, please take time on your birthday to connect with people who are important to your life. if you use social media like phones, you are likely filled with well-wishes from loved ones. Use these as a jumping-off point to start new conversations and reconnect with people who lift your spirits and support in your journey towards being your best self.

A. Connect with people who matter to you.

B. Freshen up yourself with countless opportunities.

C. It's better to give than to receive

D. This year my birthday is on a Saturday.

E. I love my birthday, though.

F. Download an app to learn a new language is also a good choice.

G. One choice is to donate a dollar amount to match your age.