—Sir, would you mind my sitting next to you?—__________. My father will sit here in a minute.
“雅鲁藏布大峡谷比号称世界最长的美国科罗拉多峡谷长46.3千米,比号称世界最深的秘鲁科尔多峡谷深2082米。”这句话运用了____和____的说明方法,它们的作用是____。
数一数左图中一共有____条线段．
数一数左图中一共有