肾脏     ____   A血液循环的动力器官

心脏     ____   B形成尿液

大脑皮层 ____   C气体和食物的共同通道

膀胱     ____   D神经活动的最高级中枢

咽       ____   E暂时储存尿液

已知一个数的绝对值等于2，那么这个数与2的和为（　　）

某研究性学习小组利用如图甲所示电路测量电池组的电动势E和内阻r，根据实验数据绘出如图乙所示的 图线，其中R为电阻箱读数，I为电流表读数，由此可以得到E＝

____ V，r＝____ Ω.

用括号内所给词的适当形式填空（每空不限一词）。

①The ____ (thirty-one) Olympics will be held in Brazil（巴西）in 2016.

②It was____  (care) of Jim to leave the tap running all night.

③— Which do you think is ____  (valuable), time or money?

— Time, I think. When time is gone, it never comes back.

④Usually, books for children ____ (write) in simple languages.

⑤— Could you tell me how ____ (succeed) in making a speech in front of people?

— Be confident. That's the point.