用边长30厘米的正方形地砖铺一段长12米，宽6米的人行道路面.
①至少需要多少块这样的地砖?
②如果地砖每平方米的售价是35元，那么购买地砖至少应花多少元?
解：① 12× 6÷( 0.3 × 0.3)
=72÷ 0.09
=800(块)
②12× 6× 35=2520(元)
答：至少需要 800 块这样的地砖，购买地砖至少应花2520元
暂无解析
Jack is a teacher of English. He is not young，but he is not old. He has a round face and black hair.He is tall. There are fifty students in his class. They all like him.Now it's in the afternoon. Look，some students are working in the classroom. Jack is there，too.He is helping them to study English. He is a good teacher， and he is a good friend of them all.
()1. What does Jack do?
A. He is a worker.
B. He is a teacher.
C. He is a doctor.
D. He's a nurse.
()2. What colour is his hair?
A. It's black.
B. His heir is white.
C. It is brown.
D. He has yellow hair.
()3. How many students are there in his class?
A. There are fifteen students in his class.
B. There's fifty.
C. He has fifty.
D. There're fifty in it.
()4. Jack is a good teacher，isn't he?
A. Yes ，he isn't.
B. No ，he is.
C. Yes，he's.
D. Yes ，he is.
()5. What are the students doing in the classroom?
A. They are walking there.
B. They are doing their lessons.
C. They are helping their teacher.