直接激动M、N受体的是（）
A．毛果芸香碱
B．乙酰胆碱
C．孔筒箭毒碱
D．烟碱
E．阿托品
参考答案：B
句型转换。
l. My father often watches TV in the evening.（改为否定句）
My father _____ _____ oftenTV in the evening.
2. The girls are waiting for a famous actor.（改为一般疑问句）
_____ the girls waiting _____ a famous actor?
3. The students are playing computer games now.（对画线部分提问）
_____ are the students _____ now?
4. My mother is watching TV now. （改为否定句）
My mother _____ _____ TV now.
下列与肝细胞癌发生无关的因素是()
A．HBV，HCV
B．亚硝胺类化合物
C．黄曲霉毒素
D．某些藻类毒素
E．中华分支睾吸虫
