下列化学式只表示一种纯净物的是[ ]
A.C3H8
B.C4H10
C.CH2Br2
D.C5H12
AC
It that Jane and Mary will be late.They to miss the party.
A.is like;likely
B.is like;are like
C.is likely;likely
D.is likely;are likely
肾素的合成和分泌部位是
A.肾系膜细胞 B.致密斑细胞 C.肾近球细胞 D.肝脏