三棱锥的中截面面积与该三棱锥底面面积的比为[ ]
A.1:2
B.1:3
C.1:4
D.1:5
答案:C
下列属于我国古代农业水利重大工程的有()。
A. 都江堰
B.郑国渠
C. 苏北灌溉总渠
D.京杭大运河
连词成句。
1. points South down
2. live Australia Kangaroos in
3. speak she in China What does
4. Japan in of Is the China east
5. Australia's see you flag Do the