题目

如图，乐乐用剪刀沿直线将一片平整的树叶减掉一部分，发现剩下树叶的周长比原周长小，能正确解释这一现象的数学依据是． 答案：【1】两点之间线段最短用正确的连接词填空。________ is lost may be lost forever.________ your father wants to know is ________ you are getting on with your students.—Lucy took a job working nights.—________ she did it is a mystery to me.________(什么时候，在哪里)the meeting will begin has not been decided.