A:-1<x<2
B:1<x≤2
C:-1<x≤2
D:-1<x≤3
(Ⅰ)证明:AC=AB1;
(Ⅱ)若AC⊥AB1,∠CBB1=60°,AB=BC,求二面角A﹣A1B1﹣C1的余弦值.
曾写下“封侯非我意,但愿海波平”的诗句,成功平息东南沿海倭患的民族英雄是( )
听独白,完成信息记录表。
How far is the school from Peter's home?
It's about kilometers.
How does Peter go to school?
He goes .
How many students are there?
There are students.
Where is the park?
It's the school.
What does Peter do in the park?
He plays with his friends.
2.87×0.7____0.7 110.9×0.3____110.9