If someone is lost in a forest( 森林 ), he needs only study the trees around him carefully to find his way. On this half of the earth, he will find that the side of the tree with the most leaves and branches(树枝 ) is the south side. Also, by checking the tops of the trees, he will find that they lean(倾斜 ) to the south too.
    Another sign( 标志物) for him to know where he is going is found in the bark.( 树皮) That is brighter on the south side.The remanining(树桩 ) of a cut tree is also a finder, for its rings can give him another sign. The rings will be thinner on the south side and thicker on the north side.
One more sign: some very small plants grow at the foot of a tree and they point to the north.

⑴____ A．book    B．good    C．look D．school

⑵____ A．student    B．Tuesday    C．June D．useful

⑶____ A．bread    B．speak    C．teacher D．eat

⑷____ A．orange    B．geography    C．big D．vegetable

⑸____ A．thank    B．that    C．brother D．those

课题研究小组对附着在物体表面的三个微生物（课题小组成员把他们分别标号为1，2，3）的生长情况进行观察记录．这三个微生物第一天各自一分为二，产生新的微生物（分别被标号为4，5，6，7，8，9），接下去每天都按照这样的规律变化，即每个微生物一分为二，形成新的微生物（课题组成员用如图所示的图形进行形象的记录）．那么标号为150的微生物会出现在（　　）

向量$\overrightarrow{a}$=（1，2），$\overrightarrow{b}$=（x，1），

（1）当$\overrightarrow{a}$+2$\overrightarrow{b}$与2$\overrightarrow{a}$﹣$\overrightarrow{b}$平行时，求x；

（2）当$\overrightarrow{a}$+2$\overrightarrow{b}$与2$\overrightarrow{a}$﹣$\overrightarrow{b}$垂直时，求x．

下列常识表述完全正确的一项是（    ）