简述原产地证明书的种类及签发单位。

手指皮肤刺伤比其他部位皮肤受伤更痛，是因为手指皮肤的_______内含有丰富的_____________。而皮肤轻微擦伤后不流血，是因为________。

阅读短文，然后根据短文内容简要回答下列问题。

    I had a wish to go abroad for a very long time. Finally a good chance came. Now I'm studying in the USA.

My wish comes true but I am not happy here. I want to go back to China because I hate the food in the USA.

People in the USA eat a lot of bread. They also like fast food and fried chicken very much. But I don't like such

food. I like Chinese food. There are many different kinds of food in China. They are all very delicious. So, I

often go to the Chinese restaurants in America. The food there is nice but it is very expensive. The American

people also like Chinese food very much.

1. Is the writer studying in the USA?

2. How does the writer feel in the USA?

3. Why does the writer want to go back to China? 

4. Do Americans like American food or Chinese food?

5. There are many different kinds of food in China, aren't there? 

下列哪项不是内脏性腹痛的特点（）.

A.疼痛部位含混

B.疼痛部位接近腹中线

C.常伴自主神经兴奋症状

D.腹痛可因体位变化加重

E.疼痛感觉模糊

微生物可导致人患病，也可应用于食品制作．制作酸奶和泡菜所利用的微生物是（　　）

A．酵母菌

B．乳酸菌

C．醋酸菌

D．曲霉

绒癌最常见的转移部位依次是（）.

A.肺、盆腔、脑、肝、 * *

B.盆腔、 * * 、肺、肝、脑

C.肺、 * * 、盆腔、脑、肝

D.肝、脑、盆腔、 * * 、肺

E.盆腔、肝、肺、 * * 、脑