如图是一个三角形点阵图，从上向下有无数多行，其中第一行有1个点，第二行有2个点…第n行有n个点，容易看出，10是三角点阵中前4行的点数和，则300个点是前____行的点数和．

秦岭的走向是  (  )                                                          

计算题：

油脂（化学式：C₅₇H₁₁₀O₆）是人类重要的营养物质，每克油脂在体内氧化大约放出39.3KJ的能量，正常人一般每天消耗9432KJ的能量，其中25%是由油脂提供．则：

    The Great Wall of China is more than 6,000 kilometres long. It winds ____ (it) way from west to east, across deserts, over mountains, through valleys____at last it reaches the sea. The Great Wall has a history of over twenty centuries. The first part of it ____(build) during the Spring and Autumn period. During the Qin Dynasty, ____(keep) the enemy out of his empire, Emperor Qin Shi Huang had all the walls ____(join) up. Thus, the Great Wall came into being. The Great Wall is wide enough at ____top for five horses or ten men to walk side by side. Along the wall are watchtowers, ____soldiers used to keep watch. Fires were lit on the towers as a ____ (warn) when the enemy came.

    It was ____(extreme)difficult to build such a wall in the ancient days without any modern machines. All the work was done ____hand. Thousands of men died and were buried under the wall they built. The Great Wall was made not only of stone and earth, but of the flesh and blood of millions of men.

骨与骨之间的连接有一定活动性的是（  ）