12的因数有____；16的因数有____；12和16的公因数有____；其中最大的一个是____。

平面向量$\overrightarrow{a}$，$\overrightarrow{b}$满足$\overrightarrow{b}$=2$\overrightarrow{a}$如果$\overrightarrow{a}$=（1，1），那么$\overrightarrow{b}$等于（　　）

阅读下列内容，从每小题所给的A、B、C、D四个选项中选出一个最佳答案。

    Attention！Sunshine Language Learning Centre will set a course and it will teach Pure（纯正的） British English. Maybe you've known some British expressions are quite different from American ones。British people use “autumn” for “fall”, “film” for “movie”. “holiday” for “vocation”, “garden” for “yard”. etc

    There are more typical（典型的）expressions that you may not know. Here are Mr. Bean's examples.

    Are you interested in it? Do you want to learn? You can learn British English well if you put much effort into it. We have some native British English teachers with much experience to help you.

    The course will be open in the coming summer holiday. The price of the course is not very high: ￥500 for one person; ￥900 for two（10% off）; ￥1,200 for three (20% off); for four or more(30% off).

    For further details, call 400-810-2345 or search http://www.BEcourse.com. Come and join us!

①各级人大要依法行使立法权，制订相关的法律法规

②政府要强化工作职责，坚持依法行政，自觉履行职能

③学校要加强教育和监管，做到严格执法，公正司法

④学生要增强法律意识，依法维护自己的合法权益

________ people visit the Great Wall every day.