A:昼夜长短的变化
B:正午太阳高度的变化
C:昼夜交替
D:四季的变化
已知双曲线Γ:x2a2-y2b2=1a>0,b>0的离心率e=2,过双曲线Γ的左焦点F作○O:x2+y2=a2的两条切线,切点分别为A、B,则∠AFB的大小等于( )
①可以节省学习时间和提高学习效率 ②可以提升自信心
③学习方法不管是在现在还是在未来都很重要 ④可以提高学习成绩
A
There are many different kinds of TV shows. Which do you like best?
A bite of China is a documentary(纪录片)that started on CCTT on May 14th, 2012. It tells the stories behind delicious food from different places in China and shows a lot about Chinese culture.
Britain's Got Talent (英国达人秀)is a British television talent show and competition which began in June 2007. Anyone of any age with some kinds of talent (才能)can apply for(申请)a chance against each other to win prize.
The voice of China is a television singing competition. It started on July 13th , 2012 on Zhejiang TV. It is like The voice of Holland which started in Holland in 2010.
Mythbusters (流言终结者)is a science entertainment(科技型娱乐)TV program. It is one of the oldest and the most popular shows on Discovery Channel. On the show, the hosts(主持人), Adam Savage and Jamie Hynema, take a scientific look at what people say or think to see if it is true.