Peter will _______ his post as the head of the travel agency at the end of next month.
A：take up
B：put up
C：add up
D： break up
____
下列关于美国的叙述，正确的是( )
甲是万能献血者，乙是万能受血者．则甲、乙的血型分别为____型、____型．
