根据设计要求地面安全阀的响应时间是（）。
A.10秒以内
B.20秒以内
C.30秒以内
D.一分钟以内
参考答案：A
The best way ________ spoken English is to speak more every day.[ ]
A. of learning
B. to learning
C. in learning
D. about learning
下列方剂，组成药物中含有地黄的是
A．一贯煎B．芍药汤C．归脾汤D．当归补血汤E．当归四逆汤
