问题 单项选择题

异卵双生小牛中观察到血型嵌合体,彼此间可进行相互的皮肤移植,可得出以下结论

A.这是由于两头小牛的基因差别不大

B.这是由于胚胎期免疫功能尚未成熟,接触同种异型抗原诱导了免疫耐受

C.这是由于两头小牛的MHC抗原发生变异

D.这是由于两头小牛都处于免疫抑制状态

E.由于两头小牛同时在母体内发育成熟,因而相互不发生排斥

答案

参考答案:B

阅读理解

It was Mother’s Day. A man stopped his car at a flower shop to order some flowers. He wanted the shopkeeper to send the flowers to his mother, who lived two hundred miles away.

As he got out of his car, he found a young girl sitting on the road crying.

He asked her what was wrong and she replied, “I want to buy a red rose for my mother, but I only have seventy-five cents. A rose costs two dollars.”

The man smiled and said, “Come into the shop with me, and I’ll buy you a rose.”

He bought the little girl her rose and ordered his own mother’s flowers. As they were leaving, he offered to drive the girl home. She said, “Yes, please! You can take me to my mother.” She brought him to a cemetery(墓地),where she placed the rose on the grave.

The man was moved. He returned to the flower shop, picked up the flowers he ordered, and drove two hundred miles to his mother’s house.

Today is the day for your mother. Send a flower to your kind and beautiful mother.

小题1:The man went to the shop to         .

A.have a rest

B.help the girl

C.buy some food

D.order some flowers小题2:The man’s mother lived         away from him.

A.2 kilometers

B.75 miles

C.200 miles

D.200 kilometers小题3:The girl was crying on the road because          .

A.she was hungry

B.she got hurt

C.she couldn’t afford a rose

D.she couldn’t find her way home小题4:After the man bought the girl a rose, they went to          together.

A.the cemetery

B.his shop

C.the girl’s home

D.his mother’s house小题5: We can learn from the passage that           .

A.the girl loved flowers very much

B.the girl loved her mother very much

C.the shopkeeper sent the flowers to the man’s mother

D.the man drove to his mother’s house to look after her

单项选择题 A1型题