问题 选择题
已知向量
a
=(3,1),
b
=(x,-3),且
a
b
,则x=(  )
A.9B.-9C.-
1
3
D.
1
3
答案

∵向量

a
=(3,1),
b
=(x,-3)向量,且
a
b

∴3×(-3)-1×x=0,

∴x=-9,

故选B.

完形填空

第二卷

第四部分:写作(共35分)

第一节 短文填词(共10小题;每小题1分,满分10分)

阅读下面短文,根据汉语提示、首字母提示或语境提示,在每个空格内填入一个适当的英语单词使短文意思完整,并将该词完整地写在右边相对应的横线上。所填单词要求意义准确、拼写正确。

Organized by the Students’ Union, we watched the newly-released

sci-fiction movie — 2012 last ______ (星期六) evening. In the movie, the    76. __________

end of our world falls on Dec. 21, 2012. On the day,______(地震)          77. __________

occur and volcanoes erupt,c______ millions of deaths and leaving            78. __________

people desperate. Our planet is d______ in an instant. People across            79. __________

the world tried to s______ the catastrophe.                                80. __________

Having watched the movie, I was lost in thought. ______ is high time                81. __________

that human beings should protect the ______ (环境) better. If we continue              82. __________

to care s______ little about our earth, we human beings will be punished               83. __________

for______ we do today. I suggest everybody lead a more eco-friendly life.      84. __________

Do remember everybody can _______ a difference.                         85. __________

单项选择题