问题
选择题
After he had finished ______ the text, he went on ______ the housework.[ ]
A. reading, doing
B. to read, doing
C. to read, to do
D. reading, to do
答案
答案：D
搜题请搜索小程序“爱下问搜题”
After he had finished ______ the text, he went on ______ the housework.[ ]
A. reading, doing
B. to read, doing
C. to read, to do
D. reading, to do
答案：D
除去下列各组物质中的杂质，所用试剂和方法均正确的是
| 物 质 | 杂 质 | 除杂质所用试剂和方法 | |
| A | CO2 | CO | 通入O2点燃 |
| B | KCl固体 | KClO3固体 | 加入少量MnO2加热 |
| C | KNO3 | NaCl | 加（热）水溶解、降温结晶、过滤 |
| D | CaCl2溶液 | 稀HCl | 加入过量CaCO3，充分反应后过滤 |