氯胺酮肌肉注射法多用于小儿手术的麻醉，首次剂量为（），给药后（）分钟即可出现麻醉作用，维持（）分钟。
参考答案：4~6mg/kg；1~5；15~25
Only after they had carried out over ten experiments ______ the decision.
A．they reached
B．they reach
C．did they reach
D．do they reach
According to the faculty psychologists, understanding and memorization of complicated grammatical rules of languages were regarded as important means of developing ______.
