题干

如图,已知BD为∠ABC的平分线,AB=BC,点PBD上,PMADMPNCDN,求证:PM=PN

上一题 下一题 0.0难度 选择题 更新时间:2015-07-24 05:29:47

答案(点此获取答案解析)

解答:∵BD为∠ABC的平分线, ∴∠ABD=∠CBD, 在△ABD和△CBD中, AB=BC,∠ABD=∠CBD,BD=BD, ∴△ABD≌△CBD(SAS), ∴∠ADB=∠CDB, ∵点P在BD上,PM⊥AD,PN⊥CD, ∴PM=PN.

同类题3

阅读理解

    South Africa is a multiethnic society encompassing a wide variety of cultures, languages, and religions. It has 11 official languages. If you want to say hello, it's "sawubona" in Zulu, and "hallo" in Afrikaans. Now, South Africa's school children may start using "ni hao" to say hello.

    The country's education minister says, the nation is adding the Mandarin language teaching in some schools. Mandarin is the official spoken language of China. That country is a major trading power for South Africa.

    A recent agreement between the two nations centers on five areas of cooperation. They include development in basic education, school books and lessons, mathematics and science, teacher training and career education and research.

    South Africa officials have not said how much they teaching Mandarin will cost. Troy Martens is an officials with South Africa's Ministry of Basic Education. She says the new partnership is extremely valuable.

    A public opinion study last year found that South Africans have mixed feelings about China. The survey showed 46 percent of South Africans do not like the spread of Chinese ideas and customs in their country, the results also showed that 60 percent dislike Chinese music, movies and television.

    But Ms Martens said Chinese trade is more important than those feelings. She said it is extremely helpful to learners in South Africa to study Mandarin as well as Chinese culture. And she said not every school will offer Mandarin.

    “Now this will not be compulsory, it will not be for every school, and it will not be for every child. But for schools that feel they have the capacity to offer Mandarin as a subject, we think it is a great opportunity for South African learners to be exposed to this international type of language,” said Martens.

    Lisette Noonan heads the 80-year-old Pretoria Chinese School in South Africa's capital. The school serves about 500 students from kindergarten to grade 12. Every student studies Mandarin.

    Ms Noonan says the school welcomes the new cooperation between South Africa and China. She said it is in the best interests of children to study Mandarin. She said that especially true with China becoming what she called “a huge economic power in the world”

同类题5

文言文阅读。回答1-4题。

【甲】若夫霪雨霏霏,连月不开,阴风怒号,浊浪排空;日星隐曜,山岳潜形;商旅不行,樯倾楫摧;薄暮冥冥,虎啸猿啼。登斯楼也,则有去国怀乡,忧谗畏讥,满目萧然,感极而悲者矣。

至若春和景明,波澜不惊,上下天光,一碧万顷;沙鸥翔集,锦鳞游泳;岸芷汀兰,郁郁青青。而或长烟一空,皓月千里,浮光跃金,静影沉璧,渔歌互答,此乐何极!登斯楼也,则有心旷神怡,宠辱偕忘,把酒临风,其喜洋洋者矣。

嗟夫!予尝求古仁人之心,或异二者之为,何哉?不以物喜,不以己悲;居庙堂之高则忧其民;处江湖之远则忧其君。是进亦忧,退亦忧。然则何时而乐耶?其必曰“先天下之忧而忧,后天下之乐而乐”乎?噫!微斯人,吾谁与归?

【乙】至于负者歌于途,至于负者歌于途,行者休于树,前者呼,后者应,伛偻提携,往来而不绝者,滁人游也。临溪而渔,溪深而鱼肥。酿泉为酒,泉香而酒洌;山肴野蔌,杂然而前陈者,太守宴也。宴酣之乐,非丝非竹,射者中,弈者胜,觥筹交错,起坐而喧哗者,众宾欢也。苍颜白发,颓然乎其间者,太守醉也。

已而夕阳在山,人影散乱,太守归而宾客从也。树林阴翳,鸣声上下,游人去而禽鸟乐也。然而禽鸟知山林之乐,而不知人之乐;人知从太守游而乐,而不知太守之乐其乐也。醉能同其乐,醒能述以文者,太守也。太守谓谁?庐陵欧阳修也。