【简答题】非特异性投射系统能使大脑皮层保持觉醒状态这一作用称为脑干网状结构的______作用,切断这一系统后,动物处于______状态。
【判断题】酵母菌营养缺陷型菌株的筛选中,对于诱变处理后的细胞,可以在培养基中加入制霉菌素淘汰野生型菌株。
【单选题】—Let's have lunch. Are your hands____? —Yes, they are. [ ]
【单选题】—Look! Lily and Sally are cleaning the school laboratory. —Let’s go and join them. .
A.
Many hands make light work
B.
The early bird catches the worm
C.
A friend in need is a friend indeed
D.
The grass is always greener on the other side
【简答题】简要说明微观经济学的理论体系框架和核心思想。
【单选题】男性,30岁,2天内呕咖啡样胃内容物2次,排黑便5次。平素时有饥饿性中上腹痛,有时饮酒。体格检查:血压100/70mmHg,脉搏98次/分,腹平软,中上腹轻压痛,未及包块,出血原因首先考虑( )
【单选题】Dinner will be ready______ . let's go and wash our hands.