用电源、灯泡、导线、开关和钨丝组成如图所示的电路，闭合开关，小灯泡发光；再用酒精灯对钨丝加热，会发现灯泡亮度变暗，原因是钨丝____ 。

内容有一处错误，请指出并订正
《宅地法》规定：从1863年1月1日起，所有南部叛乱各州的黑人奴隶一律获得人身自由。
答案： ____ 

用度、分、秒表示91.34°为____.

选择合适的句子补全对话。

A. It is Peter's bear.   B. Yes. It's my sheep.  C. Is this your bear? D. No, it isn't.   E. Whose goose is this?

A: Wow! What a big zoo!
B: Look at all the animals! They are so cute.
A: Oh. This is a bear.____
B: No, it isn't.____
A: Is that your sheep?
B:____
A:____ Is it your goose?
B:____ It's Lisa's goose.

口算．