如果一个斜坡的坡度i=1： $\frac{\sqrt{3}}{3}$ ，那么该斜坡的坡角为____度．

2015年3月15日,依据宪法修订的《中华人民共和国消费者权益保护法》正式实施,其中新增规定包括网络购物七日内可无理由退货。新增这一规定(     )

①说明法律是我们生活的“卫士”                      ②有利于保护网络购物者的自主选择权

③说明网络购物者开始成为“上帝”                   ④说明我国法律是人民意志和利益的体现

看拼音，写词语

juān zèng	nì zhuǎn	zhuó zhù	qīn shí
____	____	____	____
guī lì	dàn shēng	jiào xùn	quán wēi
____	____	____	____

阅读下面材料，在空白处填入适当的内容（不多于3个单词）或括号内单词的正确形式。

Dear Tom，

    How time flies! You ____ (study) in Beijing for nearly a month, during which you must have achieved a lot. Well, how's everything going? It is reported that the weather there is very hot and dry these days, which is very different from____ of your country. Have you adapted to it? In addition, you once complained that the food ____ (serve) there was not ____ your taste. I hope that should have been improved.

    I am glad to tell you that I will go to Beijing to take part in an English speech contest in July, ____ is not only an honor, but also a great opportunity for me to improve ____. And now I try my best to make ____ (prepare) for it. ____, I have some trouble in collecting the materials relevant and using the language. I will appreciate ____ if you give me a hand to solve the problems.

    After the contest, I am to drop ____ at your school to visit you. Please wait for my phone.

Li Hua

如表是某校120名学生假期阅读时间（单位：小时）的频率分布表，现用分层抽样的方法从10，15），15，20），20，25），25，30）四组中抽取20名学生了解其阅读内容，那么从这四组中依次抽取的人数是（   ）

分组	频数	频率
10，15）	12	0，10
15，20）	30	a
20，25）	m	0.40
25，30）	n	0.25
合计	120	1.00