How many _____________ are there?[ ]
A.tree
B.trees
C.a tree
答案:B
与幽门螺杆菌感染密切相关的是()
A.弥漫型(胃型)胃癌
B.胃黏膜相关淋巴组织淋巴瘤
C.肠型胃癌
D.胃类癌
E.胃息肉