一块三角形广告牌，底是2.8米，高是1.8米，如果每平方米需要用0.48千克油漆，刷这块广告牌的正面至少需要多少千克油漆？(得数保留整数)
解：2.8×1.8÷2×0.48≈2(千克)
根据短文理解，完成下了任务。
My name is Alice. I'm 13. I like sports very much. I have a basketball and a football at home. They are under my desk. I often(经常)play balls with my friends. I like vegetables. I often have tomatoes and carrots for lunch. I like ice-cream, too. My parents are doctors. They like watching soccer games on TV.
下列有关磨制石器的叙述，正确的是 （ ）
细胞工程的理论基础是细胞的全能性。下列哪种细胞的全能性最高？( )
