【单选题】使人患镰刀型细胞贫血症的根本原因是( )
【简答题】It is also important to _______ (select) a topic that is geared toward the right audience.
【单选题】受社会文化背景的制约而呈现出明显的季节性的 。
【单选题】When doing business in China, it is also important to establish ( ) before you invest in a trip
【单选题】引起镰刀型细胞贫血症的根本原因是 [ ]
【单选题】人类发生镰刀型细胞贫血症的根本原因是( )