下列哪一种疾病不属于胃癌的癌前病变
A.胃息肉 B.胃溃疡C.胃酸缺乏症 D.萎缩性胃炎
参考答案:A,B,C,D
阅读短文,判断下列句子正(T)误(F)。
It's December 24th today. It's Mary and Betty's birthday. They are American girls. They are twins.
They're in the same school and come home together. There's a birthday party in their home this evening.
Their parents, Mr. and Mrs. White are very busy. Twelve children are at the party. Mary and Betty have
got a lot of birthday presents from their parents and friends. The presents are all lovely.
Now everything is ready. Mary begins to cut the birthday cake. The children sing "Happy birthday to
you." They're having a good time.
( ) 1. Tomorrow is Christmas Day.
( ) 2. Betty is Mary's brother.
( ) 3. Betty and Mary's parents sing "Happy birthday to you." with the children.
( ) 4. All of the children are happy at the party.
( ) 5. Betty and Mary are in the same school.
焦油加工的主要任务是获得酚、萘、蒽等纯产品和()等粗产品。