【单选题】一般认为脊髓活动的_________机制可引起牵涉性疼痛。
【简答题】国家颁布的有关部门咨询业的规章,下列选项中正确的有( )。
【单选题】We have two foreign teachers here. One is from England, and is from America.
【单选题】Scene 视图中包括的绘图模式中,网格线框显示模式是:
【单选题】We ________ here two hours ago and we ________ here for two hours.
A.
have arrived; have been