“测定物质的密度”的实验原理是____ ，实验中用____ 测物体的质量。在“探究物质质量与体积关系”实验中，需测量的物理量是____ 。

2011年第5号热带风暴“米雷”6月22日下午在菲律宾以东洋面上生成，24日傍晚加强为强热带风暴，并沿我国东部沿海北移。26日下午在山东半岛以东近海减弱为热带风暴，26日21时10分在山东省荣成市成山镇沿海登陆，登陆时中心附近最大风力9级。据此回答：

下列是“米雷”过境时气压的变化曲线，四地中更接近台风中心的是(   )

修改：在错的词下画一横线，并在该词下面写出修改后的词。

注意：1）每处错误及其修改仅限一词；

2）只允许修改10处，多者（从第11处起）不计分。

    Mr. Grey usually went to work by subway. He liked walking from a station to his office unless it was raining, because he could take some exercises. One morning he was walking along the street while a stranger stopped him and said to him, “You may not remember me, sir, but seven years before I came to London without a penny in my pockets. I stopped you in this street and asked you lend me some money, and you give me £5. You said you were willing to take a chance to give us a new start.” Mr. Grey felt a bit of surprised and thought for a few minutes. Then he said, “Yes, I remember you. Going on with your story.” “Well,” answered the stranger, “were you still willing to take a chance?”

下列体现我国政府着力保障改善民生的举措有（    ）

①投入423亿元，用于扶助和促进就业                                      ②安排建设公共租赁住房的补助资金1030亿元

③新型农村社会养老保险试点范围扩大到全国40%的县         ④新农合和城镇居民医保财政补助标准提高到200元