在“探究滑动摩擦力大小与哪些因素有关”的实验中，小红同学用弹簧测力计匀速拉动同一木块在水平放置的长木板上进行甲、乙、丙三次实验（木块各面粗糙程度相同）：

      Yesterday when my son and I were eating dinner, I saw a policewoman walking past our house. A woman with a1look was following her.
      I opened the 2 , went out and asked if everything was OK. The policewoman said that the woman's3 had gone missing(失踪) an hour earlier. I said that we hadn't seen the girl, but wecould4.Iexplained to my son that we couldn't finish our5 right then. He said,” Be a kind person, Dad. "We got in our car and6 the girl all over the town. Along the way,a group of chil­dren were playing.  7they heard what had happened, they said they would help8 . They rode their bikes and joined us. 9 the little girl was found safe a few miles away. I was so 10to see many people help a stranger. It is a nice world.

周恩来提出求同存异方针的重要国际会议是（    ）

家庭电路触电事故都是人体直接或间接接触____ 线造成的；下列三个现象：①灯头里的两个线头相碰； ②插座中的两线头相碰； ③照明电路的开关里两线头相碰．其中可能引起保险丝熔断的是____ ．