用括号内所给词的适当形式填空。

1. Many books and magazines are         _ (aim) specifically at teenagers.

2.You should buy a dictionary. It's very         _ (use) for your study.

3. They asked me so many questions that I got _         (confuse).

4.When you buy something, you have to be        _ (care).

5. Don't believe him.  He didn't tell you the            (true).

慢性消化性溃疡的发生与下列哪些因素有关（）

A.胰岛D细胞的腺瘤

B.胃壁细胞总数增多

C.胃酸氢离子逆向弥散

D.十二指肠内容反流入胃

E.交感神经过度兴奋