洞里萨湖是东南亚最大的淡水湖，盛产300多种鱼类，湖水经洞里萨河在金边汇入湄公河，洞里萨河有罕见的“河水倒流”奇观。读图回答下面小题。

语法填空
    My husband and I were paying a visit  ____ my parents in Tucson. We went to a fast-food restaurant for dinner together. My husband went to the counter ____ (order )dishes and I stood with my parents.
    My dad is 90 ____ (year) old. He can hardly see very well and walks with a stick. I was scanning the restaurant, ____ (wait) to sit at the first table that was more convenient than others. A woman who was ____ (sit) with her son made eye contact with me and asked me to come to her. With a puzzled look on my face, I pointed to  ____ (me) and said , “Me ?” She nodded and said , “ Yes, you.” I walked to the table and she said , “ Bring your family here. I can finish eating at the counter. My son is in ____ hurry to leave anyway.” My eyes ____ (fill)with tears as she wiped down the table and guided my dad to the seat.
    I always believe that there are____ (nature) kind people in this world. This woman has set a good example to her son, ____ is a really lucky guy.

It's nice. ____ 

四联苯 的一氯代物有（   ）

某物理小组的同学设计了一个粗制玩具小车通过凹形桥最低点时的速度的实验。所用器材有：玩具小车、压力式托盘秤、凹形桥模拟器（圆弧部分的半径为R=0.20m）。

（1）将凹形桥模拟器静置于托盘秤上，如图（a）所示，托盘秤的示数为1.00kg；

（2）将玩具小车静置于凹形桥模拟器最低点时，托盘秤的示数如图（b）所示，该示数为_____kg;

（3）将小车从凹形桥模拟器某一位置释放，小车经过最低点后滑向另一侧，此过程中托盘秤的最大示数为m；多次从同一位置释放小车，记录各次的m值如下表所示：

完成下列填空：

（4）根据以上数据，可求出小车经过凹形桥最低点时对桥的压力为_____N；小车通过最低点时的速度大小为_______m/s。（重力加速度大小取9.80m/s² ，计算结果保留2位有效数字）

序号	1	2	3	4	5
m（kg）	1.80	1.75	1.85	1.75	1.90