I am very tired today. I _____ go to bed early.[ ]
A. should
B. shouldn't
C. can
D. can't
答案:A
直流供电回路接头温升不超过()℃
A、40
B、50
C、55
D、60
灶心土、艾叶均为温经止血药,但艾叶功偏下焦,灶心土功偏中焦。