如图所示，R₁=4Ω，R₂=6Ω，当开关S闭合时，通过R₁与R₂的电流之比为 ____；加在R₁与R₂两端的电压之比为 ____

【选修5：自然灾害与防治】阅读图文材料，完成下列要求。

雪崩是积雪在陡峭山体发生的一种瞬间崩落现象，运动速度快，冲击力大。火山喷发、地震等可诱发雪崩。1970年5月31日，甲市（位置见图7）发生里氏7．6级地震，距该市130千米左右的山峰发生大规模雪崩。雪崩导致乙市在几分钟内全城被毁，两万多居民死亡。

分析此次雪崩形成及乙市受灾严重的原因。

    The summer holiday is coming. I am going to do my homework every day. I am going to play ping­pong and basketball with my friends. I am going to go to the park with my friends, surf the Internet(上网), read books and watch TV every evening. I am going to visit my grandparents and help them with the housework. I am going to help my parents clean the room and cook dinner. I love summer holidays!

I am going to____ 

⑴do my homework

⑵watch a film

⑶visit my uncle

⑷go to the park

⑸do the housework

⑹go shopping

⑺clean the room

⑻cook dinner

某同学的一次测量记录中忘了写单位，请替他补上：一个人的身高约为178____，骑自行车的一般速度是5____．