胃黏膜主细胞可分泌 （）
A.盐酸
B.胃蛋白酶原
C.胃蛋白酶
D.碱性黏液
E.生长抑素
参考答案：B
解析：1.主细胞可分泌胃蛋白酶原，在酸性环境中转化为具有活性的胃蛋白酶。2.壁细胞可分泌盐酸和内因子。盐酸能使胃蛋白酶原被激活而成为胃蛋白酶，后者可使蛋白质变性易于水解。3.黏液细胞主要分泌碱性黏液，可形成黏液膜以保护胃黏膜，免受胃酸的侵蚀。
A. Noodles. B. Potatoes. C. Rice. 小题2:What drink is the most expensive? A. Milk. B. Coffee. C. Orange juice. 小题3:How many kinds of drinks are there? A. Six. B. Seven. C. Eight. 小题4:How much will you spend if you want a plate of dumplings and Beijing duck? A. ¥35. B. ¥40. C. ¥57. 小题5:Which of the following will cost you ¥42? A. Beef with potatoes,a bowl of rice,eggs and tomatoes. B. Mutton,milk, cabbage and a bottle of milk. C. Fried chicken, vegetable salad and a bowl of noodles. | |||||