题干

在托盘天平的两盘上各放一只质量相同的烧杯,在两只烧杯里分别加入等质量、等溶质质量分数的稀硫酸,将天平调节至平衡.然后向左盘的烧杯中加入8.4g铁,铁与稀硫酸恰好完全反应.欲使天平恢复平衡,则可向右盘的烧杯中加入(   )

A:8.4g镁

B:8.4g氧化钙

C:8.4g锌

D:8.4g碳酸镁

上一题 下一题 0.0难度 选择题 更新时间:2015-10-29 05:51:24

答案(点此获取答案解析)

A

同类题2

根据短文内容,选择最佳答案。

    When high school started, Sally and I became best friends. We shared many interests and quickly became very close.When high school ended, we both cried because we would enter different 1 in autumn.

    Our first term of college life was 2, so we often sent long e-mails and encouraged each other. We missed each other so much! In the second term, I found some new friends and I felt very 3 with them. These were friends with whom I could be myself and pour out my feelings. I wanted to share my new friends with Sally.

    When Sally 4 visited me at my school, we were excited.

    She brought a toy bear to me 5a present and told me about her college life. 6, something unexpected happened when I introduced her to my new friends.Her eyes grew dark and I could see the sadness in them.My new friends tried to share their friendship, but Sally seemed unwilling to accept it.I didn't understand 7the people I loved most couldn't love each other.

    Sally left. I knew she was not happy. I thought long about what had happened. I asked her many questions but she didn't answer me. I 8 that she was jealous(嫉妒). She saw me with my new friends and was afraid that we no longer shared the same experiences. She saw that I could still enjoy myself  9 her and wished she could be a part of it.

    I wrote Sally a letter to 10 she's always my best friend. I told her everyone had friends from home and friends from school, and all the friends were indeed life's greatest 11.Sally wrote me back soon. She was in agreement and felt sorry about 12 she had done.

    I think Sally and I both 13 an important lesson from it. Nothing can influence our 14  and change the experiences we've shared.We are now walking on two different paths of life. While new friends are special and exciting, old friends are 15 there, waiting to share their heart, no matter how far away they are from each other.

同类题5

阅读下面两段文言文,完成小题。

      【甲】十年春,齐师伐我。公将战,曹刿请见。其乡人曰:“肉食者谋之,又何间焉?”刿曰:“肉 食者鄙,未能远谋。”乃入见。问:“何以战?”公曰:“衣食所安,弗敢专也,必以分人。”对曰:“小惠未徧,民弗从也。”公曰:“牺牲玉帛,弗敢加也,必以信。”对曰:“小信未孚,神弗福也。”公曰:“小大之狱,虽不能察,必以情。”对曰:“忠之属也。可以一战。战则请从。”

       公与之乘,战于长勺。公将鼓之。刿曰:“未可。”齐人三鼓。刿曰:“可矣。”齐师败绩。公将驰之。刿曰:“未可。”下视其辙,登轼而望之,曰:“可矣。”遂逐齐师。

       既克,公问其故。对曰:“夫战,勇气也。一鼓作气,再而衰,三而竭。彼竭我盈,故克之。夫大国,难测也,惧有伏焉。吾视其辙乱,望其旗靡,故逐之。”

      【乙】十三年春,楚屈瑕伐罗,斗伯比送之。还,谓其御曰:“莫敖①必败。举趾②高,心不固矣。”遂见楚子,曰:“必济师。”楚子辞焉。入告夫人邓曼。邓曼曰:“大夫其非众之谓。莫敖狃于蒲骚之役③,将自用也,必小罗。君若不镇抚,其不设备乎!不然,夫岂不知楚师之尽行也?”楚子使人追之,不及。

       莫敖使徇④于师曰:“谏者有刑。”及鄢⑤,乱次以济,遂无次。且不设备。及罗,罗与卢戎两军之,大败之。莫敖缢于荒谷。群帅囚于冶父而听刑。楚子曰:“孤之罪也。”皆免之。

(选自《左传》,有删改)

       【注释】①莫敖:即屈瑕。②举趾:抬脚。③狃(niǔ):习以为常而不加重视。蒲骚:地名。④徇(xùn):对众宣示。⑤鄢(yān):水名,汉水支流。