问题
选择题
You ___ do it even if you don't want to. [ ]
A. can't
B. mustn't
C. have to
D.needn't
答案
C
搜题请搜索小程序“爱下问搜题”
You ___ do it even if you don't want to. [ ]
A. can't
B. mustn't
C. have to
D.needn't
C
（6分）请仿照示例完成下表。
| 物质 (杂质) | 选用试剂 | 操作方法 | |
| 示例 | 盐酸 (H2SO4) | BaCl2溶液 | 加入适量BaCl2溶液充分反应后过滤 |
| 1 | NaCl溶液 (Na2CO3) | ||
| 2 | CuSO4溶液 (H2SO4) |