在物理学中，磁场的强弱用磁感应强度（用字母B表示，国际单位是特斯拉，符号是T）来表示，磁感线越密的地方，磁场越强，磁感应强度B越大.

（1）在图20中，甲为某磁极附近磁感线的方向和分布的示意图，由图可知，该磁极为 ▲ 极，若在l处放置一个小磁针，当小磁针静止时，其指向应是图乙中的  ▲   .
（2）磁敏电阻阻值的大小随磁场的强弱变化而变，图丁是某磁敏电阻R的阻值随磁感应强度B变化的图象，据图线可知，磁敏电阻的阻值随磁感应强度B的增大而▲ ．图线没有过坐标原点，说明  ▲  .
（3）王强设计了一个可以测量该磁敏电阻R的电路如图丙所示，（其中磁敏电阻所处的磁场未画出）．将该磁敏电阻R放置在磁场中的位置某处，测出电阻后，利用R—B特性曲线可以读出相应的磁感应强度.
①在图甲磁场中1处，测得的数据如图20表中所示，则该磁敏电阻的测量值为 ▲ Ω. 
②根据该磁敏电阻的R-B特性曲线可知，1处的磁感应强度为   ▲    T.
③在实验过程中，仅将磁敏电阻从1处移至2处，其它条件不变，那么电流表的示数
▲   （填“增大”、“减小”或“不变”）.
④依据上述方法获得的磁感应强度B的测量值与该点实际值存在不小的误差，为尽可能准确反映空间某点磁场的强弱，你认为在选择磁敏电阻时应注意什么问题？

李梅是个好学生，她上学从不迟到。但今天上午第一节课她竟然迟到了将近30分钟。她去哪里了？原来，她是为做—件好事而迟到的。她做了什么好事呢？请你展开想象，以第一人称用一般过去时态把下面李梅的日记补充完整。（约60词左右，已给出的开头部分不计入总词数。）
June 15th, Thursday                                Sunny
Today is Thursday. It’s a fine day. I walked to school as usual. On my way to school
                                                                                                                                
                                                                                                                                
 
                                                                                                                                
                                                                                                                                
 
                                                                                                                                
                                                                                                                                
 
                                                                                                                                
                                                                                                                                
 
                                                                                                                                
                                                                                                                                
 
                                                                                                                                
                                                                                                                                
 
                                                                                                                                
                                                                                                                                
 
                                                                      

用一般现在时或现在进行时填空．

Do you think the teachers ________(have) a meeting now?

用一般现在时或现在进行时填空．

The train ________(be) about to leave. ________ he ________(get) to the station in time?