小明学习了“消化和吸收”后，对“唾液和淀粉经吞咽后进入胃中，在胃酸的影响下，唾液还能继续对淀粉的消化发挥作用吗？”感到困惑。通过老师的帮助，他查阅书籍获得以下资料：pH是指溶液的酸碱度，蒸馏水的pH为7（中性），唾液的pH为6.6~7.1（近中性），胃液的pH为0.9~1.5（酸性）。同时配出pH为1的盐酸溶液（酸性）。据此，小明作出“pH会影响唾液淀粉酶的活性”的假设，并设计了如下方案：

步骤	实验操作内容	试管甲	试管乙	试管丙
①	加唾液淀粉酶溶液	1mL	1mL	不加
②	加pH不同的溶液	2mL蒸馏水	2mL盐酸	2mL盐酸+1 mL蒸馏水
③	加等量的淀粉糊	2mL	2mL	2mL
④	水浴	37℃，10分钟
⑤	滴加碘液	1滴	1滴	1滴
⑥	观察实验现象	A	B	C

请分析回答：

对平抛运动的物体，已知下列哪个物理量就可确定其初速度（  ）

王强的身高是180厘米，比赵芳高12.5％．赵芳的身高是____厘米．

阅读材料，完成下列要求。

简介	图示	初始用途	后世演变
有刃，器形与斧类似，使用时配合长柄		兵器，起初用作刑具	后世渐变为仪卫所用的礼器，成为权力的象征
“束棒”拉丁文作Fasces，一种被多根绑在一起的木棍围绕的斧头		罗马执政官外山时，身边有12位肩扛束棒的侍卫。倘若有人犯了严重罪行，侍卫便用束棒行刑	演变为古罗马权力和威信的象征．后世成为集权和独裁的代表

从材料中提取信息，自拟一个研究题目进行论证。（要求：正确解释历史现象并认识其本质。观点明确，史论结合，逻辑清晰。）

    More than 6000 children were expelled（开除）from US schools last year for bringng guns and bombs to school，the US Department of Education said on May 8．
    The department gave a report on the expulsions（开除）as saying handguns accounted for 58 per cent of the 6093 expulsions in 1996—97，against 7 per cent for rifles or shotguns and 35 per cent for other types of firearms．
    “The report is a clear sign that our nation’s public schools are cracking down（严惩）”on students who bring guns to school，“Education Secretary Richard Riey said in a statement．“We need to be tough-minded（坚强的）about keeping guns out of our schools and do everything to keep our children safe．”
    In March 1997，an 11-year-old boy and a 13-year-old using hand-guns and rifles shot dead four children and a teacher at a school in Jonesboro，Arkansas．In October，two were killed and seven wounded in a shooting at a Mississippi school．Two months later，a 14-year-old boy killed three high school students and wounded five in Daducab，Kentucky．
    “Most of the expulsions，56 per cent，were from high schools，which have students from about age 13，34 per cent were from junior high schools and 9 per cent were from elementary schools．”The report said．