问题
选择题
把一个棱长为a的正方体,任意截成两个长方体,这两个长方体的表面积之和是( )
A.a3+2a2
B.7a2
C.8a2
D.无法确定
答案
a2×6+a×a×2,
=6a2+2a2,
=8a2(平方厘米);
故选:C.
把一个棱长为a的正方体,任意截成两个长方体,这两个长方体的表面积之和是( )
A.a3+2a2
B.7a2
C.8a2
D.无法确定
a2×6+a×a×2,
=6a2+2a2,
=8a2(平方厘米);
故选:C.
阅读理解。 | ||
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1. Julia Morley is trying to _____. | ||
A. find a job B. learn English C. travel around D. deliver milk | ||
2. How many foreign languages did Julia learn? | ||
A. One. B. Two. C. Three. D. Four. | ||
3. Julia is interested in _____. | ||
A. reading and wrting B. delivenng milk and taking food orders C. leaming languages D. traveling and playing football |