Foreign matter：Not more than 3% of stem with a diameter exceeding 5 mm．关于杂质的规定，以下正确的是：（）

Bark about 0.2 to 0.8 mm thick occurring in closely packed compound quills made up of single or double quills．Which of the following is not true（）

Use 20g and distil at a rate of 2.5ml to 3.5ml Per minute for 5 hours．实验中蒸馏提取的速率是（）