There are 15 _____ in the hospital. They are all friendly to the patients.
A:women doctors
B:woman doctors
C:woman doctor
D:women doctor
11个连续的自然数的和是154,最小的一个自然数是____ .
“xy>0”是“x+y=x+y”的( )
My hair is long. Your hair is ____ (short/long). My ears are small. Your ears are ____ (big/small).
据《通志》载:“曹氏,叔振铎,文王子而武王弟也,武王克商,封之於陶丘,为宋景公所灭,子孙以国为氏。”由此可见,导致曹姓形成的制度应该是( )