问题
选择题
________ he _______ go to the doctor now? [ ]
A. Does, has to
B. Does, have to
C. Do, have to
D. Do, has to
答案
答案：B
搜题请搜索小程序“爱下问搜题”
________ he _______ go to the doctor now? [ ]
A. Does, has to
B. Does, have to
C. Do, have to
D. Do, has to
答案：B
下列方法不能把待鉴别的物质区分开的是
| 选项 | 待鉴别的物质 | 鉴别方法 |
| A | 软水、硬水 | 加肥皂水，搅拌，观察产生泡沫的多少 |
| B | 硝酸铵和氢氧化钠 | 加水溶解，用手触摸烧杯外壁温度的变化 |
| C | 食盐水和醋酸 | 加入酚酞试液，观察溶液颜色的变化 |
| D | 棉纤维、羊毛纤维 | 点燃，闻燃烧产生的气味 |