下列试管中能够加入碘液后变成蓝色的是
| 试管号 | 试管中的内容物 | 条件 |
| 1 | 2mL淀粉溶液+2mL唾液 | 37℃,5min |
| 2 | 2mL淀粉溶液+2mL水 | 37℃,5min |
| 3 | 2mL淀粉溶液+2mL稀释的唾液 | 37℃,5min |
| 4 | 2mL淀粉溶液+2mL唾液 | 95℃,5min |
| 5 | 2mL淀粉溶液+2mL唾液+3滴盐酸 | 37℃,5min |