【判断题】若属性A是基本关系R的主属性,A可以取空值
【单选题】¿ cuál es la que no tiene nada que ver con la religión?
【判断题】力的数值为零、或力的作用线通过矩心时,力矩均为零。
【多选题】根据参照完整性规则,若属性组F是基本关系R的外码,F与基本关系S的主码相对应,则F在R中的取值可以是( )。
【单选题】It was __________she was injured in the accident _______ she didn’t come to the party yesterday.
B.
because; that C since; why D. for; how
【简答题】(reveal, novelty, dispute, immune, inspire, extract, substance, incite, reconcile, consult) 2. 这种青霉素非常罕见,能够产生大量抗菌物质。 It was a rare type extraordinarily productive in antibacterial ________.
【单选题】The asocial personality of Americans may stem from ______.
A.
the absence of a common religion and ancestry
B.
the multiracial constituents of the US society
C.
the want of a shared myths they possess in life
D.
the counterbalance to narcissistic personality
【单选题】I couldn't imagine ________ difficult it was for these badly injured victims to make it to the hospital.