18. A peculiar feature of the embryonic mammalian circulatory system is that in the area of the heart the cells adhere to one another, beating in unison and adopting specialized orientations exclusive of one another.(A) beating in unison and adopting (B) they beat in unison while adopting (C) beat in unison, and adopt (D) beating in unison yet adopting(D) (E) even though they beat in unison and adopt [D]*
答案给的是D,真是不解。为什么不选 C。怒小弟愚钝,请指教! (A) beating in unison and adopting (B) they beat in unison while adopting (C) beat in unison, and adopt (D) beating in unison yet adopting(D) (E) even though they beat in unison and adopt [D]*
答案给的是D,真是不解。为什么不选 C。怒小弟愚钝,请指教! |